Gem Flower
in an ideal world you would have said "sorry, im not into you" when he said he had a crush on you... but in an ideal world he would have also taken the hint from you not making an effort
the lesson to learn is you can never be too clear when letting someone down. Hints just don't cut it, even the rediculously obvious ones. If you find yourself in such a situation in future, have a polite word and let who ever it is know that they are making you uncomfortable. You may hurt a few feelings along the way, but sometimes this unavoidable, and you have to be selfish at times. Nip it in the bud early, and then their feelings won't have time to develop too much, and it will be easier for them to 'get over' (if they need to).
don't beat yourself up over this - its a learning experiance
so just remember:
be firm and clear if you don't feel the same
let them know EARLY
if someone makes you uncomfortable, let them know and ask them to stop
be "selfish" if you have to - your feelings always come first