Today I realized how accustomed my body has become to exercise over the course of just a few weeks. I've been crabby the last few days, no idea why and no real reason, until I packed up my workout clothes this morning. This afternoon I ran two miles in 30 minutes, my speed wasn't huge but I've never run 30 solid minutes before without walking.
I'm stress free when I run. I don't think about grading, students, really anything. All I do is concentrate on getting to the next tenth mile. It's amazing.