He hasn't slept well in a very long time.

It's always the same dream he gets. His mother's ghoulish face staring right back at him as fire rages about.

That, combined with the paranoia of Charles Xavier or maybe even Jean Grey infiltrating his mind while he slept keeps him awake for days at a time.

But then he is only human, (mutant actually, schematics) so of course he crashes eventually. He just does it directly on his desk in the middle of trying to draft up some plans for mutant power.