Just challenge yourself and do a meetup event. I was the same way, and I found that after I got the first one out of the way, it was easier from there on out. My impression was that a lot of the people I run into during the meetups are more on the introverted/socially awkward side anyways, so it's not like you'll run into people who will put you down or think you're weird if you don't talk much or seem nervous.

If you make a friend during the meetup consider it a bonus (since it's not likely you'll go to a single event and make a good friend, but it's possible), but mostly use it as a way to practice being social and something that will keep you from being alone at home. Once you feel comfortable talking to people during the meetup events, you may find it easier to move on to other ways of meeting people. As you slowly put yourself out there more and more (it's a process), you'll eventually run into people that you'll connect with.

While I realize that social anxiety is a real and serious problem, try not to let it keep you from finding happiness in life, and consider going to therapy if you aren't already (nothing wrong with that, I go for similar reasons).