Hmmm....well I had that problem not too long ago. I just decided one day that stressing over whether or not a guy likes me is a waste of energy and of thought. It is probably better for your sanity just to let it go. And hey, if he likes you then he will pursue you (call you, ask you out on a date, and so on...). If he doesn't, his loss. Also, don't be afraid to ask him if he likes you. The answer to that question can help you move on with life more quickly.
As for me, I believe there are more important things to worry about like: school, a job, family, ECT. As of now, I'm more worried about earning enough money to study abroad in Japan than having a boyfriend. I'm only 18, so I have plenty of time to worry about guys later.
"Maturity is when your world opens up and you realize that you are not the center of it."
~ M.J. Croan