Also remember that an hour of sleep before midnight has the same effect as two hours of sleep after midnight.

Don't know why, but that's what's said, apparently.

Try and get back to your normal sleeping patterns, and see how things work out.

Oh, and I envy you. I can live on 5 hours of sleep, but barely. I need at least 10 hours (over 12, ideally), and that's impossible during weekdays. You're a lucky bugger and no mistake!