Yes, you are on the path to bulimia. It's a really good thing that you've sorta recognized this and are reaching out. It will become a larger issue and be worse to deal with eventually. Talk to a psychologist or a school counselor, and your parents. It seems they would help you out immensely.
I won't judge you based upon your weight as basically everyone does. I myself am 110 pounds and people say i'm skinny when I think i'm not really, especially not as compared to most girls, just slender with big legs(partially due to muscle from walking so much). I go through bouts of starvation, but have tried to stop and haven't for a while now. I know that if I found out how to make myself sick i'd do it as well. It mostly had to do with my home life, but now i'm at college with some freedom and don't have my parents around.
If you want a flatter stomach, just do a little working out. I don't really have advice for that, but, since starting college, i've started doing yoga and pilates like i've wanted to for a while and didn't have the transportation, means or funds for. It hasn't been long enough to really see any results, but I feel just so much better after i'm done. I feel so very relaxed and pure and just good about myself, which is completely contrary to how I normally am.
I'm no one to say the following things, but I think they're true, I just can't believe them myself (other mental problems- depression, social anxiety disorder, low self-esteem, etc. Now i'm the one who's really lost.

). Don't compare yourself to other people, because you're so special yourself. You're beautiful as you are, especially inside I can tell. You're just being a little hypocritical of yourself, and can't really look all objectively at yourself.
Oh, and do not compare your body to your boyfriend's! It's so easy for most guys to be skinny at this time in their lives. They don't get fat in the same places as girls do. Just wait and he'll gain some weight in a few years, with maturity and all, most likely. If not, then he's just the freak.;p
keep in touch. It'll be alright.
~veronica