I have a lot of resilience from a lot of life experiences. This not having been my first crunch time also helped me cope - I focused on getting as much of a good night sleep as I could (typically 6 - 7 1/2 hours a night, usually ended up closer to 6 - 7 1/2 is my optimal amount), and dosed on lots of caffeine if not well-rested. Exercise is also important.

I did have to sacrifice all other interests thought during the time period though. All I know is, I'm definitely taking a vacation in two months.