2 & a half years ago I was where you are, absolutely devastated over a girl. I know exactly how it feels to not be able to sleep or eat or concentrate on anything. At one point when it was all still pretty fresh, all I could see for 2 or 3 weeks was her face, I was in a deep trance of turmoil.

How did I deal with it? I hit the drink for 3 months. Bad idea, I could actually feel physical internal pain & was definitely doing damage by drinking so much.

But I didn't have anything else going on, no job or hobbies. You seem to have a lot of that going on which is good for you.

Keep occupied. Drink little. And you should stay away from drugs of any kind.