Seeing others move foward with lives

I am 19 and am a freshmen in college.  I haven't kissed a girl yet. I haven't even been is a serious relationship with a girl yet.  I know I am not gay, because I still definetly find myself staring at atrractive females.I see all my friends and everyone around me getting into serious relationships and leaving me in the dust.  I see it in class, I see it on Facebook.  It's seriously depressing.Doesn't is suck to see a girl you have an interest in start hanging out with other guys, and you know you should of made your move sooner.  This has happened a few times now to me, and it's starting to take a toll.