You know you have PTSD when..
When you can feel someone staring at you- you turn instantly, and they quickly look away.. seeming startled that you zeroed in on them like that.
When you jump and react so much when someone startles you, that you end up apologising to them for making them jump in return.
When you hate anyone standing behind you where you can't see them.. you end up turning your body slightly to the side in queues so that you can see everyone.. even if it's just out of the corner of your eye.
When there's no way on earth that you'll sit in the middle of a restaurant.. you'll always choose a table where you can have your back against a wall, or at least to one side of you.. and if you do have to sit in the middle for some reason, you'll end up acting spacy and distant - and be a crappy dinner companion, because you're on such high alert to everything else.
When you can completely calmly handle a crisis.. but going to the supermarket makes you want to curl up and sleep for the rest of the day.