Don't quit! You will regret it later! It sounds like you're just a little burnt out right now ... take a break, pop some benzos, get some serious sleep... avoid parties and your worthless friends for awhile... watch some movies, lay in bed, and when the bad thoughts come back, pop another Xanax and go to sleep...
This happends to everyone, and it's easy to blamethe drugs, but it's really the entire combo of parties, friends, drug use, etc...
Still, as you can tell, I am not good at helping talk someone OUT of drug use - these things are forgineto me.... so, I will try to move this to The Dark Side ...
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"I am not one of those weak-spirited, sappy Americans who want to be liked by all the people around them. I don't care if people hate my guts; I assume most of them do. The important question is: 'What are they in a position to do about it?'" (William S. Burroughs)