Being single isn't hell. I know this stuff puts a knot in your belly, but that passes. The women that come and go in your life are part of your experience. Appreciate the experience, but now turn the page and start the next chapter. Don't, for a moment, let yourself believe that you have to be with someone to be happy. When you're with someone, appreciate it. When your not, appreciate it. While this probably isn't what you feel right now, you should soon acknowledge that you've just been given the opportunity to raise your fun factor exponentially. The future is pretty hard to see, and ten years from now you may be taking out a home equity for braces for the twins, and driving a minivan. In the meantime, go get a fishing boat or a motorcycle, play poker, smoke cigars, buy a (new) handgun, go to camp and get drunk. Other woman will come along. Actually, a single guy having fun is what brings them in. Go visit some old friend, one plane ticket cost less than two. Go to the strip joint. Live your life and love it.
You're getting a lot of good advice. Sean said, "Go find your self." That's words of wisdom. Jdwaynes is right on, that when the right one comes along, she may come out of nowhere and not be anything like what you'd have been pursuing. (I love his avatar.) Lilninjabuddy expounds like a guru. His thoughts on your responsibilities in a committed relationship are impeccable, but that's not where you and she were, regardless of your feelings. If only one partner is committed, there is no partnership. You may well look back one day and realize that she was the wiser. If you go out searching for another serious relationship, you might as well just tie your own shoelaces together. Let life happen, bask in the experience, and have fun while the gettin' is good.