Illness mental/physical
I'm having a really bad morning. Called out of work, massive ulcer pain, not enough sleep, rolling panic attacks and something I don't know the name of but I'm gonna call an Autism Attack.
You're in the middle of or recovering from a panic attack, and your ability to interface with other human beings shuts down totally.
You can listen, you can hear, you can form replies but you can't do much more than shake and make inarticulate noises.