What is the Equation?

As fall break comes nearer, for each day that passes I become exponentially more tired, grumpy, have more to get done, back hurts more, and just plain over working. It must start in ernest at 10 days because I made sure I got 7 hours of sleep last night, and I'm exhausted. My first thought of the morning, "how many more days?" and "can I possibly hold on that long?" And it just escalates from here.
But then I have a break, and everything's fine, no one gets hurt.
Thoughts for a Tuesday morning.