What should I do to improve my body image and self-esteem?

[Sncooljay3]

I been struggling with the size of breasts and wanting them to be a tiny bit bigger since I was in the middle school. It happen when I was talking to use to be friends call me a flat chest. They are size 32B or C or and they haven't change since I was 11 or 12 years old. My boyfriend says that I am beautiful and all and should be happy with my body and mentions time to time he loves my small boobs but I don't believe him and I been made fun of my body, height, and the size of my small boobs all my life. I tried to improve my esteem for 10 years and I am on the verge on giving up. It improve a bit then I got pregnant at age 21 and given birth to my and my boyfriend's baby I simply started to hate my postpartum body and I feel like my boobs have gotten smaller. So please someone give me tips to help me feel better about my body and breasts' size.