I think you're already on the right way with classical music, long walks, reading books, etc. (except for the Internet addiction). I guess if you keep on doing things you like you will recover. All the best to you.
One side-benefit of the absurd working hours I put in over the years was that it took away all my time and broke my obsessive gaming habit. I suffer withdrawal symptoms from time to time when I see other people having a nice time at their battlestations, but I like to think I've learned some self-control.