If your confidence has gotten that low towards sex, say fuck it and get a hooker man.
I know most people would probably consider that horrible advice, but when you do get with a girl you actually like and are going to have sex with her, you won't feel like you're taking a shot in the dark.
And if you arn't comfortable doing that, get a few drinks in you, goto a bar, and you're bound to open up to someone, and at that point getting someone to go home with won't even be too hard.
Again, if you arn't comfortable going for some easy snatch, or if you don't dirnk, try and improove on your personality in social situations. I mean, if you're considering giving up now, what is there to lose?
However, don't give up man, keep on truckin', if it makes you feel any better my old man used to be jacked back in the day (he was about as muscular and fit as you can get without using suppliments, he also had secondary education and a steady job) and he never even got a date until he was 30 years old. Just goes to show it never is too late.
If you want to talk er whatever, just throw me a PM, hoped I helped.