Gee it sounds like it’s pretty bad being in bed for 4 days without eating or drinking.
Have you been to a clinical psychologist? Sounds like you might benefit from proper psychotherapy. Also, you have talked to your GP, are you or have you been on medication for your anxiety/depression? Might help with the mood regulation a little bit.
I understand what you mean about not telling work- my workplace is always boasting about its employee assistance program but I’m sure when push comes to shove they wouldn’t tolerate days off.
I was only thinking today how there should be more provisions for mental health time off without consequence in our legislation...
You mentioned social anxiety, do you have any friends you can talk to? Not even necessarily about your mental health but just to chat - we are evolved to need social contact with others and so this is like a powerful antidepressant in itself.
Here to fill that need somewhat anytime you want though.