1. Go to gym, get fit it helps with self confidence
2. Read this book https://www.amazon.com/Awkward-Science-Socially-Thats-Awesom...
3. Go to therapy!
4. Don’t rush, don’t push yourself to go to parties etc. small steps, start with going to coffee shops so you are around humans, look in people’s eyes on a sidewalk and smile to them, then gradually start with small talks with barista.
Good luck !