The straw that nearly broke this camel's back

I am sitting on the floor, surrounded by stacks of literary analyses, sorting them into piles - those who did well on the assignment, those who had some part of it that was on track, and those who utterly failed. 3 roughly equal piles. I am trying to write an eloquent example paper to show the students what I'm actually looking for. I am rewriting and rescheduling the next two weeks of lesson plans. And then - a large, creepy beetle crawls across the top of my laptop. Last straw. Sanity = gone.