Sarahplainandshort mentioned the meyers-Briggs index, and I always come out as a very strong INTP which is about as inwardly focused as you can get. My mom is hugely extroverted, and for a long time, I thought that was how I was supposed to be too. I felt so inadequate in comparison to her.

As others have said, I've accepted at this point that if I'm going to be around people for an extended period, it's gotta be followed by solitude and quiet for my sanity to have a shot. I used to have no comfort talking to strangers, but my participation in my 12 step groups has completely changed this for me. It feels commonplace and natural which has convinced me of my malleability. This is big change for someone who once didn't get a haircut for 6 years because I'd have to talk to the stylist.