I am addicted to chocolate?

I am addicted to chocolate, every day i eat loads and if i don't have any i become grumpy and unpleasant to be with. I am 14 and i do boxing, cycling and water polo so i'm not fat and i have great fitness levels. I go the gym twice every week but i would feel better if i didn't eat as much and i'm sure if see more benefits from the gym and boxing if i cut down. How can i stop because if i eat this much as an adult i will definitely be unfit and fat so do you know any alternatives or ways of cutting down? Thanks.