Hopefully this post could help future candidates that have trouble sleeping before the exam day. Maybe you are reading this post in the middle of the night trying to get asleep the day before the exam lol I did it too.
I passed Level II and III with 1 and 2 hours of sleep, respectively, as my anxiety got the best of me. I am not the smartest, yet I believe - as @DPBass88 said, “a few hours of less sleep will not take away hundreds of hour spent studying.” Well said by the way.
Knowing that I would not be able to fall asleep the day before the exam, I tried to have 6-7 hours of good sleep 1-2 weeks before. I also consumed healthier and protein-rich food, such as fish, chicken, etc and no junk food. One day of no sleep will not crush weeks of quality sleeps.
Eat breakfast! I ate oatmeal, fresh milk, and banana, while during the PM break, I ate whole-grain bread, tuna fish, and plain yogurt (to give a little bit of glucose for my brain). My point is that daily dietary intake is the integral part that should not be overlooked.
I also did 1-2 mock exams lacking sleep. It helped as it gave me a glimpse of doing the exam under exhaustive condition. Also, it will give you confidence boost, in case you weren’t able to sleep a night before, as you have done it previously.
Lastly, you have to trust your months of hard work. Not being asleep is not something I would recommend, but if you do, it is very possible to pass the exam. Trust yourself, you can do it!
P.S.: It is only based on my experience. Each of you may have different strategies and circumstances.