You know, there is no road map or instruction book for parenting. You do the best you can which it seems like you do. Take a breathe, dobt get ahead of yourself. I know that you are concerned about your baby but wait until you know more, lots of things are not life sentences to anything bad despite what you may see in the media.
The other stuff, I’d highly recommend that you sit down with a therapist, you have a lot of things going on most of which it seems as though you were just a victim of circumstance. It’s fairly common to not know who you after having babies and the shift from being everything but you (mom girlfriend etc). But you have more going on then that that you nerd to sort. Don’t feel guilty for feeling things but do take care if you.
There’s nothing wrong with being on the spectrum. There’s alot of good therapies and techniques now to help.
For the rest of your issues, you should talk to a therapist yourself. It’ll help you sort through your feelings and give you some unbiased input. It helps.
First, step back and take a breath. Focus. Prioritize. Being a first time mom is hard, even harder when you’re a first time mom and it’s twins. I’d like to say it gets easier, but it doesn’t. I was a first time mom at 19 to twin girls. I grew up with them and struggled along the way. They’re 18 now, high school graduates, college students and starting their own lives. You’re never going to be okay with your babies growing up. Never. I have two younger ones also, and I go through the same thing with them as they grow. With your sadness of them growing up, will come so much happiness also. My twins were born 7 weeks early and both premises. The doctor told me to prepare for them being delayed in comparison to their peers and that they may have developmental delays. The doctors were wrong. I have two smart, beautiful (sometimes lazy) twins. But if one or both of yours have developmental delays, there are programs and support groups. Look into those if that’s the diagnosis. While it’s important to have a good relationship with your family and your fiancé’s family, it’s more important for you to have a healthy relationship for YOUR family, meaning you, your fiancé and your children. Doesn’t mean cut the family off, but your focus should be directed to your home before any others. For you, I would suggest speaking with a therapist. They can help you work through your personal issues and can also help you cope with your children, your family, boundaries etc. The MOST important thing to remember is that YOU GOT THIS!! One day at a time! Being a parent is a never ending learning experience!
My granddaughter is 3 and has ASD. I wouldn’t change her for the world. Her autism is just a part of her. She was the same baby the day before her diagnosis as she was after.
First pray. Continue being a mom and continue to pray. P. U. S. H. Pray until something good happening
Step back take a breath forget everything. You ha ve so many things going.it has overwhelmed you don’t worry about what could. .be just take one day at a time… God bless take care.
Not the end of the world if kid has development issues. I don’t understand why so many people are scared of hearing their kids have autism or ADHD. It’s like you guys are more scared of the label and would rather them not be “labeled” then get them the care they need.
Depression causes over welming but have the rest untop of it is causing you to be way over welded so look around find five things and describe them then find four things feel them describe how they feel taste one thing discribe how it taste forgot what three and two are but this helps with anxiety and a lot of things for me
May God help you, my prayers for you🙏’s
There is loads of help out there don’t be afraid to ask contact family services and tell people how you feel
I’m sorry you are so sad
Ow sweetheart …you have so much going on …you are an amazing person and mother …you deserve the best… look into some support counselling for you
ASAP…you may also still have post natal depression…you got this…things WILL. Work out …but you must look after you first ok 
Hon first off you are an amazing mother to twin boys . That’s wonderful.
So you realize you have depression. Go and get on some good medication. I know many people who are talking medication. It is no one’s business, and you need to take good care of yourself.
Many children have issues. But the doctors and therapists will help you in every way . That is what they are trained to do . I don’t know where you live , but in America we have special schools to help as well. We have many services to help children with special needs . It is amazing how much help is available. So take one thing at a time . Love yourself snd get on some medication for depression. Then you will be able to help your sons with one thing at a time .Start praying and asking God for help every day . God loves you snd your sons more than you can imagine. One day at a time , God will not fail you !!!
You have connected with your family, but realize you are going to have to set your priorities.
Have early intervention come in and assess the kids. They offer help until they are 3 yrs old. Sensory is a challenge but once you know the triggers, you can help manage it. Set some boundaries for yourself and rest when they rest. Make a schedule for them and keep to it as best you can. Ask for help for a few hours each week or even a few times a week to do laundry, watch the kids while you rest, help cook a few meals for you etc. Little things add up to big help.
Ur doing a good job! Always BELIEVE that, can you sit down and make a list from one to 10of all the things you need to do and then switch them around to what’s important! And what can wait!
Motherhood is hard but you must think of you and then your children, , and ask for help, it’s ok! See your dr to discuss what Is happening and don’t forget there is help out there! 
Give yourself a holiday, leave babies with your family , take a full day out at a park. some mall or just a long bus ride get back in the evening… spend time alone
Pull up big girl pants take deep breath , breath.you got this