There is a cure for this kind of eating disorder, and you are right to want to quit right now. If you are really ready, and you sound like it, then go to www.shrinkyourself.com and sign up for the twelve week program...you might also want to ready the book which is also described on that site...there you will be taken through the cure process step by step.....Your only other real alternative is to go into therapy with an eating disorder specialist.
I am about your age and am recovering too. My struggle is not to overeat; I used to eat platefuls of brownies and cookies, and then get angry with myself, and the disorder started.
This really helps me: I wear a rubber band on my wrist and I wrote the word "remember" on it. You can only see the word when it is stretched out so no one else can really see it. It sounds corny, but every time before I do something that may trigger the disorder I see it. Maybe you could think of a word that might help you, and write it on one.
Its not even close to a cure, but it is what really helped me. Best wishes.