WAKE UP!!!!! Haha, here are some tips for you:
Caffeine: If you are able to study with caffeine this could help you stay awake
Don't slouch: A lot of times people slouch at their desk or lean over. Even worse, is using your arm to prop your head up. And even WORSE, is putting your hand on your chin and covering your mouth a little. If you aren't breathing well, the lack of oxygen can make you sleepy. So make sure to take a few deep breaths every 5 minutes or so. This will help with brain activity too.
Chew gum: Cinnamon gum is supposed to be best. Apparently there was a study done that actually shows that chewing cinnamon gum can help increase brain activity.
Don't lay down: If you are studying while laying down or in bed, move!
Don't study right after a large meal: A large meal can make all the blood rush to your stomach and make you sleepy.
Jump around, get the blood flowing: If you feel yourself become sleepy, take some deep breaths, stand up, do some jumping jacks, some push ups, or dance around a little.. get the blood flowing again
Turn on the air conditioning, or put a fan on yourself: It is proven that if you are warm, you get sleepy. That is why casinos keep it sooo cold. keep yourself cold, and you'll stay awake.
I bet you if you use a few of these, you will not get so sleepy! Good luck