What are the signs of postpartum depression?

I had my baby 3 months ago and up until recently I’ve felt fine but now I feel like I can’t do anything right and I’ve been self isolating myself because I don’t feel comfortable doing things now that she’s here, I know Postpartum is normal but I don’t know how to handle it. I get overwhelmed and tired and I just feel burnt out and my appetite is not there but I force myself to eat because I’m breastfeeding and I know my baby needs the nutrition, basically I need help figuring out how to deal with it. I don’t want to talk to my family about it because i feel they will think im just overthinking everything and overreacting.