Welcome. Quitting is a big step, but quitting shouldn't be a scary as what is going to happen, eventually, if you don't.
If you are at a large state school, there is probably counseling available for students. Colleges are aware of problem drinking and have programs in place to deal with the issue.
As far as what to do at night, study. Go to the library and see what the other people who don't drink are doing. Strike up a friendship or two with people who have prioritized school ahead of getting drunk.
Good luck.