Okay, the first thing I would suggest is to stop going to bars and go to other places. I mean, you said yourself that the bars don't work. Same with the internet or dating websites. Go to your local park or go to the beach and you might run into someone there.
Confidence is key. I know you already said that you aren't that confident but it's like a law for girls that the boy should approach first. It's screwed up (some girls do approach guys, however) but I've been in too many situations where my friends (all female) are too scared to go up to the guy they like because "I don't want to sound desperate by going up to him first" or "I don't want to sound desperate by sending the first text". And personally, I like a man with confidence. But too much confidence just makes you look like a player. I would honestly be so flattered if a guy walked up to me while I was shopping or walking down the street and say "I just wanted to say that you're very pretty. Could I get your name/number?" It's gentlemanly but shows that you have some confidence. A few girls might still deny you, but remember, beauty is in the eye of the beholder, as lame as that sounds lol.
It is difficult to understand women lol. But know that some of us are clueless too. We don't know if we should send signals because what if the guy doesn't like us? Your anxiety matches the anxiety that some girls have. Also, some girls might just think they look weird or can't flirt so they don't.
You can still continue to do dating websites (I've heard that some are very successful) and go to the bars. But remember to get out more and also, find a job. You'd be amazed with how many new people you can meet working, from McDonalds to some desk job. Also, smile! It is incredibly difficult for me to do this because I'm so shy, but I started smiling a lot to random people I passed in the hallway during my senior year that I made a whole lot of new friends. Just a quick grin would make some people smile. It shows that you're friendly. Some girls might not have talked to you/approached you because you appeared unfriendly. Just smile, don't cross your arms, and, amazingly, chew gum. A recent study showed that people who chew gum look friendlier and more social than someone who doesn't. Also remember to shower daily and dress well.
Good luck! I hope I helped :)