as scary as it may seem, i think if you suffer from social anxiety the best thing to do is to remove the MMO aspect, for a given period and see how well you can operate without it. If you identify that you have a problem, try and see if you can get out there and meet new people. Take up a sport, or something else to eat up your spare time. If you give it a chance it can be rewarding - but it has to be something you want to do.
just my own 2c from my experiences.