Thanks so much for all of the comments and good thoughts. I think they helped!
The reader's digest version of what happened is this: Right in the middle of this HUGE project both my departments are spending hours upon hours of overtime working on, one of them got fired yesterday. I honestly can't blame the company for doing it, although it's extremely unfortunate for the girl who got fired. As well as for myself since I'm shortstaffed until they can find a replacement, which will probably be a few weeks, and my other two employees since their jobs are being turned upside-down to provide coverage. My departments were understaffed as it was, and this just pushes us over the edge. Now nobody can get sick or take a day off because the Hag (remember her?) refuses to "share" any of her employees, a handful of which are trained to cover us.
It's just a big fat mess. Oh yeah, and I found out today that starting the 31st they're changing who I'm reporting to. Again. This would be boss number 3 in as many years. Neat.
But like I said, your thoughts and prayers must have helped because I'm in a surprisingly good mood now. Even though I'm exhausted, and even though the Hag was being a hag to me all day, and even though another annoying coworker tried (quite unsuccessfully) to throw me under the bus this afternoon, I'm feeling good. Like, confident even. It's been a long time since I felt confident at work. That's not enough to make me want to stay for any longer than I have to, but hopefully it will last long enough to get me through the worst.
And now - it's a three day weekend! And it's supposed to be sunny and 80 degrees all weekend! And I'm going to enjoy every last minute of it while pretending my job doesn't exist!