I've felt like that too, and I still don't know if I'll ever experience a relationship. But one thing I have learned as of late is that you need to shift your focus. I've recently escaped a very bad, depressive, unproductive mindstate. A key factor in this was learning that you have to stop longing for companionship, and start appreciating the parts of your single life that you do have. Only by stepping back and away from the problem, can you see how to fix it. Maybe I'm still alone, maybe I will always be, but I'm a lot more productive than when I was beating myself up and feeling like crap. You can't fix a problem until you step out of it.