Nearly had a heart attack... Skyrim got all crazy on me, I somehow accidentally closed it out, and when I reloaded, I was back where I was when I started five hours before.
I thought I'd cry, but then I got to looking in my folders for save files and could clearly see that more current ones were available. I could go in and manually load them back to more or less where I left off, but if I just picked "Continue" it wouldn't do it.
Then I remembered that until I got home from work today, my PC was a day ahead and I had set it back... So it was loading from what it thought was the most recent save progress. Deleted that save file and ta-da, it works like normal again.
No sads for me and I can go to sleep feeling a little bit better now.