At the best of times, I'm a poor sleeper -- I'm prone to waking up in the middle of the night, and even the slightest sound can often wake me up. I'm not actually one of those people who is comfortable with only five or six hours of sleep a night, but that's often what I get.
But that's nothing compared to true insomnia. On a night like the one just passed, I'll spend essentially the entire time tossing and turning. The mental tension of the day turns into muscle tension in the night, and tension is my bane when I'm trying to sleep.
Intellectually, I suspect that I get an hour or two of sleep in the interstices, but I can't prove that; certainly, I'm awake during at least some of every hour of the night. And it feeds on itself in a rather horrible way -- the more I want to sleep, the more it eludes me. When it gets bad, sleep is for me very much like flying in the Hitchhiker's books: the only way to succeed is to forget about how badly the situation sucks. (Which is, of course, very difficult to do when you're sleep-depped.) And there's no description for just how unpleasant it gets after a few days; lack of sleep simply crushes you slowly.
Sigh. Time to break out all the tricks -- the light yoga exercises, the sleep-restriction techniques and so on. And thank heavens that I expect this crunch to last only a couple of weeks, after which I can slowly rebuild my health again...