What do I do about this guy that I like?

There is this guy that I like in my spanish class. We flirt all the time and we always talk on a social site. When we talked on a social site, he said that his computer was dying, so he asked me for my number. I gave it to him, because (obviously) I like him. We talked for, what seemed like, ever. Then I called him the next day, and he said, “Can I call you back when I am done cleaning the kitchen.” I said, “sure.” He NEVER called me back (this was 2 weeks ago) We talked on a social site again. Later he was like “I have to go.” He didn’t even say that he would call me or anything, like before. I talked to him on April 6th(the day before my birthday) and asked him if he was comming to my birthday party. He said, “Probably”. I told him to call me. He said “o.k.” Then we got off.

I haven’t talked to him since then. He hasn’t even been on a social site.

Why is he avoiding me?