Lexi's right - quitting and going alum (or in my parlance, terminating and going inactive) are 2 totally different things. If you go alum, you can still be involved after you graduate, and that might be something you'd turn out to love. However, I know that sometimes there are issues like housing, etc that make it impossible to go alum while still in school.
Or you can make other friends outside the sorority and look at it this way: you have your friends, and then you have your "job" which is the sorority. That might make it a little more palatable. I'm not going to outright say quit because I'm learned from this board how important it is to be Greek at some schools in the south.
Plus, this is a bad time of year - EVERYONE is burnt. Think about it and let us know what you decide. Good luck
