Jet Lag Inversion.

Since Chicago is six hours behind, since last Wednesday when I got back to London, I had been going to bed at four and waking up at noon. This Monday I had a nine am class. I got up for it, having gone to bed late as usual, and it hurts, but I thought the payoff would be getting onto a normal sleep schedule. And indeed, I fell asleep by 11pm last night, but woke up again at 4am, and couldn't get back to sleep. Then at noon, I fell asleep in the library. My jet lag inverted itself! How did this happen?