It can feel like you're the only person who's never had a relationship, but at 16, there are still plenty of people like you who haven't. I didn't meet anyone I liked enough to want to be with (and who liked me back) until I got to university, and he's the only person I've ever kissed. It's probably unusual for all of your friendship group except you to be in long term relationships (and generally people don't tend to stay with the person they were with at 16 anyway - only one of my friends has done) and it might help if you did make friends with some other people. You say you've tried going to clubs and stuff and not had any joy; keep trying because there will be people out there who you get on with enough to become friends with!
And with regard to boys, don't go looking for a relationship and try not to see every boy you get on with as a potential boyfriend, because you could end up going out with someone for the sake of going out with someone. I knew I didn't want to do that, so when at 15 a male friend asked me out, even though I wanted to know what it was like to be in a relationship, I said no because I knew I didn't feel anything for him romantically and probably never would. Relationships are nice and when with the right person are fantastic, but you don't need one. It'll happen when the time and the person are both right!