Grass always looks greener at this age. You see one of your friends in a seemingly happy relationship and you suddenly feel like you have a hole in your life that can only be filled by a pair of trousers. Pull yourself together! You're 22, you should be out living life, not worrying about being single.
Personally, I prefer dating. I meet a guy, we have a few drinks, we text for a while in between going out every so often. I just enjoy the ride until it fizzles out (and no, this doesn't mean I ever do anything sexual with them). I think that's better: meeting people. If something more ever comes of it...well, that's out of my control and who knows it could be something pretty amazing, but I don't actively date guys with the prospect of a relationship in my mind. Do that and you'll be disappointed every single time.
And hey, long term relationships at our age (I'm 21) rarely work out. I have a few gay friends who haven't even been in their relationships for 6 months and they're already arguing all the time and come off really miserable when we go out. Relationships at such a young age tend to have very, very short expiry dates.
You wouldn't buy a bottle of milk that goes off tomorrow, you buy the one with the date most far away and get your use out of it!