Damn bro why are you not at the gym????? You're 6 ft and 310??? You could drop some of that weight and be HUGE!! I'm 5'11 and 147 I'd kill to have a few extra pounds!!

This might sound harsh but I say this out of pure love man because I really feel your pain and I know how hopeless you feel. Get off your butt! If you're not working and don't have much to do that might be why you feel so crappy! I know it's difficult..

Maybe no one has said this stuff but you gotta get busy. Believe me once you make an effort you'll start feeling better. As long as you're not doing anything about your "problems" you're gonna feel bad.

Online dating=BAD IDEA!!! You think your self esteem is in the crapper now? Get with someone who's struggling with the same things and see how that goes.
You might not be anti social. Your social anxiety might just be because how you view yourself.