I'm so glad I found this thread. I am also introverted but only in certain situations. I was a police officer for 13 years and was fine talking to people in that sort of situation, but stick me in a party where I don't know anyone and I feel completely sick. I don't understand why I have such a split personality.
We recently moved to a new area where we don't know anyone, this meant I left my job and I am currently a SAHM. I promised myself before we moved that I would make a real effort to get to know people and talk to the other parents at the school gate etc. I have failed miserably and am starting to get lonely now.
My friends and family are a two hour drive away, so I still see them fairly regularly. I just wish I could make some local friends here but I just can't bring myself to do it.