I get extremely apathetic. In times when 'normal' people would be under great stress, my emotions just switch off and I stop caring about anything.
That's how I flunked out of school.
teacher: "If you keep going on like this you're gonna be held back a year!"
me: (motionless, blank look): "Oh. Bummer."
I sort of have it now. I should be studying but when I have the book in front of me and see how much I still have to do I just freeze up and lose all motivation.