By the time you are finished, you are a zombie. Expect a few months to be "back to your 'old self.'"
Oh, and a thing about liberty - yes, it is "your" time, but keep this in mind: OCS liberty, just like everything else, is a TEST. "They" inspect you, brief you, and send you out into the World for 24 hours. Guess what? "They" are out there too, and they are ALWAYS watching. (It isn't too hard to figure out what the bald guys in khaki pants are doing within a 50-mile radius of Quantico...) Plus, liberty isn't just a time to drink a few beers - it is also a time to get stuff done/study, if you need to.
Just like in life, if you are alert 24/7, you'll be fine.