Breast changes after baby

I’ve always been small but I was always told if you have a baby you’ll gain weight..that was a lie. My boobs went from 32DD to 32A after pregnancy. I’m struggling a lot with liking my body since having my son. I’m just very unhappy with not having my boobs I’ve had since I was 12. I’m also struggling with gaining weight on top of that. I only weigh 100 pounds. I think I have an eating disorder honestly