I have a big exam in the morning where I have an hour to write a 1500 word essay from what I can memorise from the information Ive written out. I know that when I fall asleep everything Ive remembered so far will be wiped clean and I just don't have time to go over it again in the morning before the exam and I'm always way more focused when I'm tired Ive used the stay up all night technique a lot before and it always sees me good but around 4am is the worst, I start passing out and I need to know how I can stop myself falling asleep. Any tips?