1. As someone might have touched upon, trying to find girls is the most obvious desperation move possible, and it's one of the easiest ways to become even more sad. You've kind of admitted defeat, so you have that going for you. If a girl likes you, they will come to you. If they don't like you, they won't. You're entering your senior year of college, and it doesn't sound as if you have many female friends, so to be honest? You're probably alone for a while. But that's a position that can be advantageous as well.
2. Try to become more... interesting. Quirks that simply don't pop up anywhere else in your school. If people consider you weird for them, FUCK 'EM. Weird is the best place you want to be. It detracts the people who you hate and attracts the people you might end up liking. For instance, I have a # of quirks - I can speak in multiple accents and dialects of English (American, British, Scottish, Canadian, learning Irish), as well as a native Russian accent, with a minor usage of some other European accents. I use a lot of metaphors. I have a rather astounding intuition and understanding of most people I meet; I can usually finish their thoughts for them, predict their next thought, figure out motivations. I sometimes can recall deja vu experiences fast enough to tell of the experience right as it's happening, which scares the life out of everyone around me at the time. I have 3 passports. I once built a functional skeeball machine out of scrap wood, a picnic table out of hard wood, and a stuffed rabbit out of duct tape, all within 2 months time, for no reason other than sheer boredom. I can pull a triple all-nighter for fun.
I'm sure you can find your own uniqueness. Something inherent about yourself that few other people have. Territory where few others have tread. It is probably the best way to make friends, simply astonishing them with something they not only haven't really seen before, but something they never would have thought of doing.
3. Do not give a damn. This ties into the previous point of not giving a fuck if people think you're weird, but you shouldn't be bowing to pressure from anyone else. If you feel doing something is right, then just do it. If it sounds badass and you know you won't get seriously injured, do it. The tape rabbit thing was me being bored for a day, buying three rolls of duct tape, going to a friend's house and crafting that shit over 5 hours. This was done despite having absolutely no experience crafting anything exclusively out of duct tape. The final product didn't look the greatest, but just the idea got me applause for the project.
We generally like people that can think they can do something that feels right, and act on that, even if it backfires. Watch the backs of others and they will look out for you too.
4. A summation point. Ease up, be funny. You're probably not going to get the girl you want at this point in your life, so relax, take a few days to get over that realization, and start thinking about the positives in that. At this point, the only thing that should be limiting you is your morality. My advice for this summer would be to try and find yourself. Figure out what you want to do, what kind of person you want to be, and don't be afraid to look bad to others. You'd be stunned at the number of people that will come to you, talk to you and be friends with you if you are an unequivocal badass.
And that's all I have to say.