It sounds like you have two things going on here. 1) You feel socially awkward and 2) Your friends aren’t inviting you to parties.
I’ll address the second thing first. Unless you’ve asked your friends not to invite you to those parties (because of thing number 1), then they don’t seem like very good friends to me.
I enjoy a big party, but I know plenty of people who prefer small gatherings of friends. You might want to find friends who are, like, more in sync with you. This leads me to thing number 1.
Maybe ask yourself what you like in a friendship.What does friendship mean to you? Is it about having thoughtless fun? Sharing interests? Talking? Connecting on an intimate level Playing games? All of the above?
Once you know what you want—and what you don’t want—then seek out people are want the same things.
Respect your own boundaries and limitations. If you’re not a big party goer, then don’t go to parties. If you do better one-on-one with people, that’s okay. From there, you can then take small risks to make the comfort-fence bigger, to coin a phrase.
In order to build confidence, you have to take risks. And acknowledge yourself for every triumph big and small.
Like, when Eric was sixteen, he was scared to death of defying his dad. But once he got the Vista Cruiser, I encouraged him to take a risk and drive out of town—when Red explicitly told him not to. We wanted to go to the Todd Rundgren concert.
Was Eric a little freaked? Yeah. Did the Vista Cruiser break down on the way out of town? Yeah. But we figured out how to pay for a new battery and got to the concert anyway and had a great time. And when we got back home, Eric didn’t get into any trouble—even though Red had a feeling Eric had disobeyed him.
From that moment on, Eric took more and more risks until he grew in his self-confidence. Did all his risks go perfectly? Uh, no. But that’s okay. He wouldn’t have known what he could do or become unless tried.
Give yourself a chance. You deserve to have people around you who respect who you are. If you respect yourself, you’ll attract and seek out friends who respect you, too.