I'm really tired, but I have class in a little less than an hour.

I could take a nap, but regardless of alarms, I may sleep well into the time allotted for class.

I could stay awake, but by the time we get to the middle of class, I won't be able to stay awake.

This requires some thought...however, I have not the energy for that. I think option one is going to win...let's hope I wake up...