Hey man, I totally know how you are feeling. To include the dope smokin. I used to do that all day long too. The only difference is I was already out of school, I did have a girlfriend but I treated her like **** (usually cuz I was high and lazy), and I was working but I was in such a slump I would only work like 2 hours a day and was on the verge of getting fired.
Well I'm not here to pitch the Army but that's what turned my life around. It was hard good honest work. Made me feel good physically and emotionally. Made me realize I have a lot more in me than I thought. I know you are still in school but maybe go to an Army summer camp or another organization that is big into the physical and mental stuff. It really did help me. I ended up marrying my girlfriend and treating her much better because I realized what I would be giving up if my life stayed its course. I don't plan on being in service forever, but I am greateful for every minute because it teaches me that my mind is the limit and I have met ALOT of very cool people. (plus you get to shoot guns