Ask HN: how to recover after long stretches of work?

I just finished up a major course project in operating system design, and it has me feeling a bit burned out. Think 10-12 hour days of intense coding with 6-7hrs of sleep. Not terrible by any means (I'm sure this is the norm for a lot of you), but not an ideal schedule I could keep up. I'm closer to needing 8 hours of sleep and being to do 9 hours of productive work a day (anything more I can't sustain healthily, I've found). So violating what my body needs for the last few months has led me to a "micro burnout", with symptoms such as lack of concentration, fatigue, some mood swings, etc. I figure you guys get the idea. What do you guys do to recover as effectively as possible after these long-lasting bouts of effort? EDIT to add that my main goal is to be able to get back to working hard ASAP. The stuff I'm learning and my summer job are really exciting to me and I want to make sure I can get to those in good shape. Cheers