How am I going to stay awake through school tomorrow?

I stayed home today, cuz I wasn't feeling good, and I slept until 3 in the afternoon which is probably why I can't sleep now, even though I took 20 mgs of melatonin. It's almost 5:40, I'm getting up at 6:15... I'm gonna have some serious issues staying awake today. Any suggestions besides coffee and exercise?