for me it's an unknown fear of what's out "there". the more i stay inside the worse my fears become. it's a bad cycle for me to get caught up in.
what was suggested to me in therapy to overcome this is to gradually go out...like to places i feel safe, in my case, barnes and noble. like places that don't have a lot of stimuli...walmart would freak me out when i allow myself too much staying inside. gradually i''m not as afraid if i take baby steps. i still isolate sometimes but i give myself the pleasure of that for a defined number of days. then i make myself go out cause in the long run i know it is healthier for me to do so, jme.
since the stress in the outside world bothers you perhaps the "safe place" concept would work for you too.
another thought on this for me is that i have this life to live only once. i don't want to put too many walls up cause then i would be missing out of the good things i can find in my world.
try to allow yourself some risk taking. safe risk taking.
do you talk about this with your pdoc or t? they may have some good suggestions.