I'm a compulsive eater. What should I do?

The only time I don't compulsively eat is when i'm on a strict diet to try to lose a pound or two in a few days, and I feel really good because I know I absolutely cannot eat junk food. So I really don't even think about it. But when I just try to eat normal and eat what I want I completely splurge, go over board and cannot control. I'm only 16 and struggling with my weight is really putting a stress on my life.