I'm young, have my life ahead of me .. why am I doing this?

Hi, sorry for the completely angsty first post, but I'm just so tired of binging.

I've probably been overweight most of my (admittedly teenaged) life, but I haven't started binge eating until recently. About a year ago my doctor told me I'd lost weight. That was probably due to my anemia at the time, but it still made me hopefully and I did a one eighty. I stopped eating as much, and I've dropped from 252 to 207lbs, but recently, since a couple of months ago, I guess I've taken things to extreme. I don't eat much for a few days and I tell myself that I'll start eating normally again once I've hit one sixty (my goal weight at the moment). And then .. after a few days of barely eating cereal the dam will burst and I'll end up spending a whole day (or a few) just stuffing my face with sweets and chips and everything I know I should only take in moderate, if any, amounts of. And then, of course, after a day or two of eating so much my stomach hurts, I'll feel extremely guilty and usually start to not eat again. And then another dam will burst, and the whole cycle will restart.

This is killing me. I make good grades, I take piano and am in band, I'm in the school chorus, I'm in the gifted class, and I could go far but not if this keeps up. I seriously need help. I might as well kiss college goodbye if I don't change.

Can anyone tell me how to at the very least moderate this? I can't stand it any more, it's like a skeleton in my closet .. and a bunch of candy wrappers.

Hi, Tia! Maybe this is a way to have control over everything that's happening in your life. It sounds like you're involved in a lot of things, and that can be good, but it can also cause stress. Being made to feel not good enough or unattractive or being bullied can also contribute to this.
I think you have to find other ways to feel in control of your life, healthier ways. Have you had any therapy?