As for not freaking out, I try to remember some sort of saying I once read; it went something like, "People aren't thinking about you as much as you imagine they are. You aren't that important to them". The point being, each of us are the centre of our own universe and because of this we mistakenly believe that somehow we are more significant in others' lives than we actually are. We foolishly think that our humiliations, in particular, are as obvious, influential and memorable to others as they are to us.
I guess overall it's valuable to recognise which instincts are not realistic/appropriate and remember to ignore them when they come up. It's hard to do this in the moment, because everything is telling you that those instincts are 100% right. But sometimes you just have to mentally slap yourself and say, "for goodness sake, just stop that!"