I want to thank everyone for the responses and support. It was a big help to me and I apologize for taking so long to say so. On those days when I'm feeling really low, I'll go somewhere else after work--like the mall or the bookstore or a cafe--to unwind a little. That was a really great tip and it never occurred to me because I'm cheap and try to avoid all temptation to spend money. But wandering around the mall in the evening after a bad day sounds like a perfect de-stressor. I'm also making sure to get more sleep and more exercise which seems to be helping.

Thank you everyone!!!