My daughter is 11. She rotates to her dad’s house and ours. She has her own room here and can be alone when needed. Lately when she comes home that seems to be her main objective is to be alone in her room. Sometimes I hear her talking to her friends over the phone which is great. Tonight you could tell she just got depressed and wanted to be alone. She said she didn’t know why. I tried to get her to talk a little bit but she just didn’t have any words. I asked if she wanted to hurt herself and she said no. She’s currently in her room I told her when she’s ready to talk to let us know. I’m sure its hormones and such but how do you handle it? I don’t want her to feel like she has to hide away if she’s sad but I want to give her healthy space as well. Any suggestions? Recommendations?
First off your doing great by showing her support! With my experience having my kids and I get busy and kids need our attention had to slow my self down with my stuff - and my kids! - I have another son who requires allot more attention and just inviting my son for one and one time, helps improve his mood. Also physical activity helped allot because if I would let my son he would just stay in his room with the door closed - art therapy helped enrolling my son in a big brother big sister program helped a bit too. Having fam and friends take my son out was a game changer. Think all kids deal with this perhaps and we just got to guide them that they can’t stay in the mood for to long! 
I was like this as a kid and still am as an adult. I just like my space. My parents put me through all types of therapy because they thought I was “broken”. Turns out I’m just super introverted. My dad gave me things to do solo that didn’t require a lot of communication if I didn’t want it. I got really big into art and slowly my family joined when I needed help and or wanted company and so on. Im pretty sure he also did it so my mind wouldn’t wander to other things I would keep supporting her which you’re already doing a great job. Being in a two parent house hold is hard for kids she may still be adjusting. If she’s open to the idea of therapy maybe start there. I would only go there though if you feel like something really may be wrong and her not just being introverted.
Just let her know you are there for her hugs pick her some flowers little things do matter everyday leave alittle something special at her bedroom.door like a little note to tell her how much she is loved 
That age its a struggle periods hormones body changes boys nasty friends bullies hope she feels better soon just be mum its hard being responsible for little hearts when they hurting if she doesnt improve maybe take her to talk to someone she doesnt know sometimes that can help goodluck mum
Note times & circumstances when she seems glum & try to figure out if there’s a pattern. Ask if it’s friends, guys, teachers, bullies, if she’s unhappy with something about herself, her period—anything you can think of. She may not want to talk about it with you but may nod her head if you guess correctly. Once identify the problem schedule a time to brainstorm solutions together.
Tell her you are worried she has lost her “spark” and ask if she’d be willing to talk to a counselor.
You are doing great. Hangin there.
Kids start to develop more complex thoughts and feelings around this age and going forward but they don’t always understand it nor have the tools to get through it. Being support is the first big thing you’re doing that is wonderful…keep on checking in and letting them know they aren’t alone.
Second would be to help them manage their stress or upset. They don’t necessarily need to be able to put it all in words to do this… it can be as simple as having a drink and snack whilst having a random chat thats child lead, it can be journalling, it can be going for a walk or watching a movie with you when they aren’t feeling great. Yes alone time is something we all need to process, but if it gets to the point of isolating, that can be an issue. Just gently encourage to come to you and make the time for her. Feeling connected, grounded, and knowing there’s an option there to discuss what ever they like…good or bad in a casual way will help them not take on everything and internalise their stress.
Outside of those self care kinds of things, id say counselling if you’re growing concerned. They have the tools needed to help identify what’s going on and teach your child how to get through that (and you too). Some times having an outsider is easier to open up to if kids are worried about hurting either parents feelings or causing problems in family settings.
My daughter is 15 and we have an amazing open communication relationship. Sometimes at that age they don’t know why they feel the way they do or how to put it into words. I have always told my daughter I experienced the same things at her age and it’s normal. I tell her anything she tells me is private and only between her and I. I have also encouraged all my children to find an outlet- writing/ painting/ drawing, anything to get out those emotions and feelings. My daughter writes and paints, we often paint together. My son writes, draws and plays guitar. When either of my teens are feeling down or whatever, I always offer something to do with them. Nothing big, watch a movie, create something together, go for a walk, watch funny videos, bake, anything.
The biggest things are trust and support. My daughter who is 15 is hardly ever in her room. She’s always doing things with me and her siblings. Sometimes asking her about specific things, or giving her the words that might associate what she’s feeling makes all the difference. Also at that age girls in general suck, one day someone is your best friend and the next they’re not. It’s a crappy feeling. Ask all things. Good luck with your daughter, I hope you both find a way to communicate!
You’re doing great. She may open up when she ready. I always give my bonus child the option if you’re ready to talk, you will. If not then you aren’t ready. I always say I’m here for you, my child when she comes she in her room too. She 10 be 11 in a few months. I think they like their space and the quietness lol. She may be just quiet and doesn’t know what to say. I get like that too. Someone always asking me if I’m ok lol. I just don’t always talk lol. I also have depression. Sometimes there is nothing to really say.
Get her a counselor asap. These things can go sideways way faster than our minds can track. Kids live in a mega stressful world that we don’t.
Have you talked to her dad and asked him how she does when she is there ?
Changing placing every week can be hard and exhausting. She might feel like she doesn’t belong anywhere.
Try to ask her what she wants and where she feels more comfortable staying.
Counseling is always a great option, she might feel more comfortable taking to someone else .
I would start by reaching out to her dad and see if she acts that way at her dad’s house too. If she doesn’t it may have something to do with wanting to stay at her dad’s and that could be why she doesn’t want to speak about it with you.
One thing which we don’t think about with custody changes which is the same for adults and many humans is transitions. Transitional changes as a human behavior have a lot of anxiety attached to them. If you think about the day before going back to work we get anxiety and are less happy compared to the other days before work. Or when a vacation ends we get depressed the day before going home. Try planning something simple and special the day you change to your house like grocery shopping where you pick out special treats for the week for your house and a special favorite meal plan for one or two days. Perhaps a movie night where she gets to pick that night and a few nights after that. Some counselors say children need a sense of hope to cure depression. So maybe do a hope allowance where she can earn credits to earn, do, or buy things. It doesn’t even have to be much. 50 cents or a dollar here and there. Maybe buy some of her favorite small things and add them to a hope chest and get raffle tickets. Whenever you are proud of her give her tickets. Whenever she earns enough tickets she gets to visit the hope chest to pick something out. I spent over 30 hours with a psychotherapist to have her give me one tip that my son needed hope. It really made a difference with divorce, transitions in custody, and depression. That’s not all it, but instilling and providing hope and assisting in positive transition between homes is very important and helpful.
Get her a locking diary that she can take back and forth. When she is ready to be social again I would have a talk with her. Let her know she can always talk if she wants or needs to and you won’t judge or anything like that. You can also let her know if she wants to vent thats fine to. I tell my kids that parents naturally want to solve problems, so if they just want to vent they can just say, “I want you to listen, I dont want you to fix it.” But I would explain hormones if she doesn’t already know. Also I would let her know if there is anything at dad’s house that is upsetting her, she can tell you without it getting back to dad that she said anything. Let her know that you just want to support her in both households and you support her and her fathers relationship, but that you understand sometimes its hard to tell a parent when something at their house is upsetting because you dont want to hurt their feelings, so you just want her to know you are there as an ear, no judgment for her, her dad or her dads house. And finally, let her know if she doesn’t want to talk, that’s fine, but if the sadness doesn’t go away then she needs to write it down (hence the diary) because then she can get her feelings out without having to discuss her feelings with an actual person. Hope that helps and hope she feels better
Your doing the right thing…give her options and her space…but ask what’s going on at dads…
Encourage her to not isolate but to stay around others even if she is just in someone’s presence. 
Give her a list of self care ideas and let her know that someone is there for her if she needs to talk about anything on her mind. https://www.schoolcounselor.org/getmedia/b30a19ec-7b7a-4011-9d4a-5ad6df6db39a/Coping-Skills-Stress-Mgmt-Resource.pdf
Take her shopping and to eat! Get your nails done and make her feel special! She will be more likely to open up to you if she feels close to you!
Not sure where you are located but our school system has a partnership with an organization for short term virtual therapy which gives the student 8 free therapy sessions. Sometimes just having someone to talk to that’s removed from the situation can help
It’s great that you’re supporting her. I would take her out for something fun to do just you and her
Maybe take her to a therapist.
Get her out of the room and into bein active. Activity is the only thing to help until they feel ready to talk.0
Ask her if she wants to watch a movie with snacks and just be there with her.
Firstly your doing a great job, I’m not sure if this will help but when my daughter was going through this I bought coloured hair bobbles, I took the red ones and the black ones and gave them to her, I explained if she was feeling down she was to wear a red one on her wrist and if she was okay a black one, when I come home from work I’d just pop my head in her bedroom door check her wrist and if she was wearing red one I’d get bathed grab some snacks and jump in bed with her and we would watch a film, talk if she wanted to if not I’d just be there and stay with her, it just gave us that one on one time to talk about what was bothering her when she needed someone to talk too and if she didn’t want to talk i was just there supporting her through her not so good times, it’s a tough age she may need counselling or she may open up to you and you can help her through it l, either way good luck xxxxx
You can get her into therapy like the others here have recommended, OR you can go to therapy yourself and use the therapist’s expertise to find ways to help her. May help you to talk to a professional about your concerns and discuss different ways to handle this. It’s also really great to model to her that if she needs or wants someone else to talk to, there is nothing wrong with therapy. Transitions can be hard on kids. It kind of sounds like she feels like a “guest” at dads so when she comes home to you, she just wants some space where she can be at home (especially if this is exclusively coming home from dads). Just remember you are a great mom and being there for her is the most important thing.