It's simple, your allowing yourself to be hung up over this person, don't be so selfish as to think that this is the only person you will ever like. Instead meet new people, expand your horizon socially and become someone who doesn't let small crushes become blown out of proportion. People go through what you are going through EVERY SINGLE DAY, heck probably every hour, you can't let yourself get hung up on it. It happened to me once, I said oh well and moved on. Trust me, it's only the start, life is more than love anyway.