I noticed that coffee makes me pee way too often whereas I do fairly well with some types of those "tea energy" drinks. Those cans only have 30mg caffeine and my body responds well (prob because of the lower caffeine content).
I drink coffee like no other. There is no way you could get me to stop for an exam. I agree with @"Dr. Yamata".
I had a Monster energy drink in my water bottle for the break as well. I didn't crash at all.