Also, with the fear of not sleeping before the exam, I know Phloston is going to say "get 10 hours" but for some people, like me, I always get 5 or less hours of sleep before major exams. I anticipate I will get around 3 before the Step 1 exam. On some of my most sleepless nights, I scored in the 97th+ percentile for my shelf exams. I think the key is making sure you get enough sleep in the week prior to the exam, or in your case, these next 2 days. That way, even if you only get 3 hours of sleep, you're in a sleep surplus and it doesn't affect you as much. Adrenaline and caffeine will keep you focused for 8 hours. Imagine American soliders in combat during Wold War II, tired as hell, but remaining vigilant as ever for fear of a creeping nearby enemy. Your enemy is Step 1. Your vigilance is supreme, no matter how tired you are, and you will win.
Edit: eh, forgot this forum might have IMGs....replace my WW2 analogy with the soldier of your own country, the same principle applies...