i would not go overboard with avoiding things. dont pick a job without any human interaction, instead just go just a bit slower than you used to. you might be tempted to retract fully into your comfort zone but your comfort zone can and will shrink if you give in to your sa too much. do whatever youre capable of doing without burning yourself out imo.
in the past, i made the mistake of full retreat at least twice and it cost me years. so for the past two years or so i have been acting outside my comfort zone a lot, not really flooding myself, but doing stuff im afraid of a lot, and i have made a lot of progress. the program will be more specific on how this works and why it hasnt worked for you so far.
anyway, if you were able to hold down a job that required you to do all these things you certainly are capable to have social interactions outside of work as well. i suggest you start with doing more things just after a few weeks of therapy. regarding relationships, i found it much easier to get a girlfriend than to get anything work-related done. dont think that is a special quality of me, in fact the topic of dating etc. has been one of my biggest fears for years.