To mimic the tests start sleeping 3-4 hours a night, eat very little, and have someone give you a workout prior to your test.
Seriously though you'll be fine if you're in shape... each DI has their own stuff but mostly it's just you have to stay back straight and either pushing or in front leaning rest with knife hands the whole 2 minutes.
Nice avatar btw...
I slept from 2200 until 0445, with the occasional restroom breaks. So I am not sure why you were not getting you full night sleep. And food, food was delicious. I ate like an athlete everyday (Maybe that is why I lost so little weight).