Chevca, cheer up and remain positive. I too have been there and there are ways to get over it... and I have infact gone through this same sense of urgency and isolation feeling. At 23 and dropping out of college without a real social network (school ensured I couldn't have any other time commitments) and never having a date or kiss by that point was very difficult to manage. It kinda drove me crazy actually. But life isn't over and there are some important things to keep in mind.
First of all, both socially and for long term relationships, you need a significant and consistent time commitment. Think as though you are going to know a girl for months and months even before she thinks of moving past the 'just friends' state. You can't immediately meet a girl and then expect to have sex or marry her or something... maybe it happens once in a while but you can't even think like that. It'll drive you crazy. You have to become friends with her first. This sex on first dates thing is something for movies and pornography and stuff and something in the minds of men which we need to get rid of. Men and women are biologically different in that way and women value the relationships. Remember that!!!
Another thing, about what to say and act like. Be the most friendly, funny and caring guy out there and be POSITIVE, even if you don't feel like this on the inside. You are not the only person out there with crap in their life. People gravitate toward toward the people that are so happy and fun to be with that they forget all their problems. Act this role as best you can. My strategy is to avoid saying anything bad about yourself or the world unless it is absolutely necessary. Maintain a facade that you don't have any problems and people will like to hang out with you more. Most likely, you'll become happier and forget you had those problems to start with.
Thirdly, when something does happen... don't overreact. I've done this way too many times and read way too much into things. It often doesn't mean as much as you think it means so don't grow attached to someone you don't really know very well. Talk to and flirt with all the girls you meet and expect them to do the exact same thing. Make sure you go at a pace that you are comfortable with... if it feels weird you are probably doing something wrong. Forced relationships often end badly.
And finally, keep trying and learn from your mistakes. This isn't easy and it takes time but it's possible. You've got to expect things not to go right at first and every once in awhile afterward but stay persistent. It should be a lot of fun once you get the hang of it.