I like this one guy, but he doesnt (apparently)?

Ok so i i have a HUGE crush on this guy and im pretty sure (like 75%) that he likes me back. Problem is, a few weeks ago, i heard from one of his buddies that he asked this girl out. I felt really insecure over the next few weeks, and am still glum about it. I always thought they hated each other like arch enemies, because they both piss off one another a lot! So... i think he just wanted attention. The question im asking here is how am i going to get over this?