The Shift-Worker's Dilemma

For various reasons, I've only been managing to get five or six hours of sleep for the past three nights -- or, rather, days -- and as a result I am feeling incredibly wiped out right now. I'm still on night shift for another week, though, which leaves me with a dilemma: should I force myself to stay awake for another four or five hours so as not to throw my schedule off, or should I just give in to sweet, sweet sleep and worry about next week when it gets here?

At the moment, I am leaning strongly towards Plan B...