I don't know your situation, like if you're a freshman or a senior or whatever, but you should be able to pick if you get a roommate or not. At least at my school we do, and if there's a dean of disability at your school, you should be able to request a single. Once again, though, that's happens at my school.
Otherwise, I have no advice for you because I had a roommate who would be an awesome roommate for a lot of people, but it still bothered me. I ended up moving to a single in the middle of the year.
But that's me, and I get tired of people after a certain number of hours and her just being in the room bothered me.