My social life began to turn around when I started getting more used to rejection. I thought rejection was the end of the world, until I learned that "studies have shown" the popular kids in school get rejected from games etc just as often as the unpopular kids, they just don't get as upset about it. I think that was a bit of a turning point for me.
I realised that all my life I had been searching for a couple of special people to be friends with and rejecting everyone else. Now I think that it takes 10 strangers to make 1 acquaintance, and 10 acquaintances to make one friend. That means for every friend you want to make, you need to mix with 100 people, so it's time to get started. It's probably much more than 100, I just made the numbers up. Probably the odder you are, the MORE you have to mix with ordinary people in everyday life, not just wait for some person to come along who is probably a bully anyway.
Another thing that helped is my husband telling me that he didn't like his friends at first but they kept turning up and eventually they were friends. That was the opposite of my "reject most people" approach and made me think.
PS I found it was very very important to "keep in touch" on a regular basis online. Keeping in touch, without trying to fix anything, builds trust in a magical way because people think "this person has kept in touch once a month for a year and nothing bad has happened to me yet" which is the main reason for rejecting others if you think about it - "something bad might happen." So if you feel rejected and give up quickly, often you are missing out.