Tired and Frustrated

An all too often occurrence these days. I'm beginning to think that these exams, rather than testing our statistical knowledge, are actually an endurance test. For how many days can you stay wound this tightly without completely losing your mind? I fear I am rapidly approaching my limit. I can feel my brain ceasing to function, reading the same paragraph over and over again without it making any sense and making no headway on this problem I'm not sure how to solve. Sure, you think. It's 6 pm. A totally acceptable time to hit a wall and take a break. But this is after my extra long 2.5 hour "lunch" break and far too many smaller breaks throughout the day reading blogs and news sites and just basically slacking off. The truth is, I've lost the ability to work for more than an hour or two at a time. Which would be ok of those hours were split by lots of brief, 15-20 minute breaks. But they aren't. I put in an hour or two in the morning. Break for way too long for lunch. Work another couple of hours in the afternoon. Break for way too long for dinner. Then half-assedly work another couple at night, stay up way too late anyway, and start over again the next morning. And that ain't going to cut it. Ok, enough bitching. Nose, meet grindstone.