Getting very depressed over loneliness in college...what to do?

I feel extremely empty not being in a relationship and some nights I just want to curl up in a ball and die-it's the worst feeling in the world. That said, it's not logical for me to get involved with someone at this point in my life because i'm a college student and will be going to grad school shortly and would have to deal with long-distance and other problems that may arise. What can I do in this situation? I feel at a loss.