So you've just pulled an all nighter, how do you get through the day?
edave: Do you have a caffeine addiction already? If so, I'd say keep up drinking some caffeine just so you don't have withdrawal problems on top of being tired.I don't drink caffeine, but here's what's worked for me: 
1) Nap several times during the day, if you can, even 20 mins is enough.
2) Drink lots of water, eat some food- I hear bananas are good.
3) Avoid making any important decisions today
4) Keep moving around and listen to some musicAnd most importantly, get to sleep early enough tonight to account for the fact that you've now got 5 or so hours of sleep debt. I doubt you're going to go to bed and sleep 13 hrs, but even planning to sleep 10 or 11 hours tonight will help your schedule a lot through the rest of the week.