You were up all night and there is nothing that you would rather do than just close your eyes and get some sleep. Unfortunately, it's not an option. You have to go into work and perform as if nothing is wrong. Here are some tips to help you make it through the day:
Dive into your work. Don't put it off; just jump right into it. Adrenaline might carry you through. You may even get so focused on the task at hand that the day flies by. When you're tired, there is nothing worse than just sitting around.
Focus on one task at a time. When you're exhausted, you can easily become confused. Therefore, it's best to focus on one thing at a time. Finish one task and then move on to the next one.
Do tasks that are easy for you. Save the complicated tasks for when you've had a good night sleep. If you attempt these tasks when you are tired, you might make mistakes. Try to find some mindless work that you usually avoid.
Caffeinate. If you're trying to cut down on coffee, give yourself a break for today. You might even want to have a second one!
Take a walk. When you're tired, fresh air can really help. Go outside on your lunch break and take a walk. You may find that the exercise combined with the cool breeze gives you just enough energy to tackle the afternoon.
Treat yourself to a nice lunch. If there was ever a day to treat yourself, it's today. Reward yourself for getting through the morning with a nice lunch. Don't be afraid to splurge; it's not like you do it every day. After you finish your delicious lunch, it'll be just a few hours before you can go home and get to bed.
When you're tired, work is about the last thing that you feel like doing. Unfortunately, the world doesn't stop just because you had a long night; reports still need to be written, meetings still need to be held; and customers still need to be served. So turn off that snooze button, get showered and dressed, and just take it one step at a time.