I had to stop my internship 3 years ago because of social phobia, it was nearly the end of me. Haven't been able to get a real job either.
Still trying to fix it. I've noticed that taking small, but strong steps into the right direction seem to help. I use my therapist to discus the next step. Do what you can without becoming overwhelmed. That's how I'm trying to do it.
Be proactive, but don't rush it. :3