Yeah. Same thing ahppened to bme from staying up to watch teh WC Final (it was on at 3:00 in the morning here).

Make sure to drink lots of water. Have a breakfast that's abotu 1.5x bigger than your normal breakfast.

Snack during the day. Not trash like chocolate bars, or chips or anything like that (although they will do if you can't get anything else), but cookies or something with at least some carbs in them.

DO NOT HAVE A BIG LUNCH. That will FUCK YOU UP. Have a light lunch and snack thorughout the day.

Also, if you are able to, see if you can sneak somewhere and have a 20 minute nap. That will set up you up for a few hours. However, I know not everyone has this option, so if you can't do that, keep your self engaged with projects, not monotonous crap, if you can avoid it.

That should do it. Good luck.