Very similar to both of your accounts, restaurants are a toughy for me, it’s hard for me to enjoy my time with the people I’m sitting with because I almost always can’t check out of other peoples conversations, I don’t even want to listen! It’s just overwhelming and I can’t drown them out. Which makes me very quiet and not fun to eat with.
At work I have also had this occurrence, with sudden groups of people all chatting at once and this was usually my que to take a bathroom break, or go refill my coffee. Sometimes I’d just step away and sit in a quiet bathroom stall for a couple minutes, or take a quick lap around the office (this was common in my office, we enjoyed getting our “steps in” haha, but it had a duel purpose of helping me escape for a moment)