I have low self esteem?

Im a 15 year old girl and I feel really badly about myself sometimes but most of the time I just feel fat cuz I have alotta extra weight ONLY on my tummy :( and I have really low self esteem and idk what to do about it and I'm bulimic and it's more of a stress release make myself feel better kinda thing and I don't enjoy it cuz I kno it's bad but it's like an addiction and I just wanna kno what I can do about my low self esteem :(