>>2 here.

I left school at 16 and did nothing for a year, except a job at a supermarket. It was very depressing. Going to college and then university helped me put my life back on track.

Like you, I didn't have many, if any friends and felt very anxious in social situations. Usually I would never talk to anybody, still don't, but moreso than I did.

Going back to education involved me getting on a train packed with people my age, it was horrible. I stuck out college and I was offered a place at a univerity course, now I'm about to finish it and get a degree.

I didn't make many friends at university, but I have a lovely girlfriend, and I'm close to getting a good job abroad.

I think if I didn't go back into education, I'd still be working at the supermarket, seeing everyone else succeed.

tl;dr:
Go back to education, Choose a subject that you are very interested in (easier to talk to classmates about, I did Games Development, so nerds. I could talk about videogames)