haha, aw.
its a horrible feeling isnt it? don't you stay in touch with him.. next time you see him get his email address/number or something and stay in touch, or meet up and talk about whether he has his eye on someone or something..
many times i've liked someone who i've assumed may like me back but they never do, it always helps to ask them if they like anyone, dig it out of them and if they say they do and mention someone else, then seriously sod it. you';ll be holding onto someone who probably couldn't give a toss about you.
mind you some guys love to play hard to get.