Is he sending me mixed messages?

So there's this guy that I met last year while working on a school project. We didn't really talk alot then because we were both busy with school and relationships. This fall however we have some cles together, and so we started talking over facebook more. It's always super flirty, and he always brings up relationships. We're actually really similar in terms of what we want/need in a relationship. He's hinted at the fact that we should hang out, and I've brought it up before and he agreed that we should hang out. But this week when I asked if he was free, he said he was really busy with school (midterms are starting) and that he wouldn't know for sure until the next day. But then he never got back to me about it. Then today I guess at the end of lecture, my friends and I were leaving out the bottom doors and he was standing nearby to ask the prof a question, I didn't even notice him but I guess he was staring at me/checking me out for awhile. Should I even bother with him considering he blew me off ?