How does lack of sleep affect your body and brain?

I'm sure you'll get first hand knowledge (which is better than anything I can offer in that area) of when you hallucinate. What I do want to advise, though, is that you watch the caffeine intake. When you near the middle-end of it you'll be very tempted to up the caffeine dosages (if you choose to use caffeine) and it is very easy in that stretch to overdo it. Too much caffeine is very bad for your heart and brain. Just be careful.