I've been in the exact same situation, and have had to force myself to be social. As in, "if I don't go out to the grocery store, I will eat absolutely nothing today". With some help from social support, good practical field manuals, and more recently anxiety meds, I can force myself to go out often enough to prevent the anxiety from building up again. I've greatly expanded my comfort zone. Meds are also very, very helpful tools for dealing with these issues.