Totally Confused

There's this boy I have known for several years. In November, I suddenly fell in love with him. And I really thought he felt the same way, but now I don't know what to think or what he wants. There were situations where we held hands or touched each other, then HE kissed me once but since then nothing has happened. We never talked about all these things. I'm just too shy to ask him about it because he's acting like nothing's happened. Sometimes he looks like he wants me to say something and the other day he acted so cold like he didn't recognize me. It's driving me crazy. No matter what I do I can't get him out of my head. I can't sleep anymore. What should I do?