I feel the way you do, but have been diagnosed as having social anxiety as well as BP 1. I'm not sure that the social anxiety isn't the problem making friends now. I have no history of BP behavior with anyone I meet (I just moved to a new city), but still feel the same way as I did as a teenager. I always think of that song from "Phantom of the Opera" called "Learn to Be Lonely". It makes me cry.

Isolating isn't healthy, so get out there even if you're just a bump on a log. I joined a couple of groups I have an interest in and haven't made friends yet, but it is nice to be acknowledged by and in the company of others. My goal is to get out of the house once a day. I don't always meet it, but feel accomplished even if all I do is go to the grocery store and am able to have good eye contact and a mini-conversation. It's all work for me, but in my best interests, part of managing my bipolar.