the last few days I have been feeling so depressed. I barely ever eat I feel like I have no time to get anything done. I'm having strange feelings toward my SO

Feeling like since now my body is different and I don't feel good about myself that he is talking to someone better when I have no reason to question him. Breast feeding is making me feel like I can't produce enough for my baby. My nipples are torn up im I'm pain feel like I might have a infection. My milk supply is getting smaller. I feel like I'm on the verge of tears all the time. I don't know what to do.