Feeling un-approachable

I wasn't sure if this fit in one of the categories or not but I was wondering if I could get some advice... Yesterday I was at my friends 16th birthday party and she was inviting some of her guy friends from jujitsu (4guys) and all of our friends (7girls) through out the night some of the girls went home and some of us had, had way too much to drink and my friend and I had bearly nothing. I had spoken a little bit to each guy but ever time they seemed to be taken away by something or someone and later on into the night everyone was in a couple (guy+girl) and my friend and I where all alone. Am I un-approachable?? Was I not interesting enough?? Did I need to be more drunk to be confident around guys or for the guys to pay attention to me?? I have been single most of my life and I'm getting to that stage where I really want a boyfriend and out of 4 guys none of them showed any interest in me but found company with every other girl. Why am I always  the one left of my own?? 
Can anyone give me some pointers of guys or something??