The bloody thing was undoing one character at a time, which... I have no idea. I did close it, and thought not saving changes would take care of whatever I'd initially done, but nope. Fortunately, I've been able to retrieve the important snippets I've sent to a couple friends, but I'm recreating the rest.

I'm also on the hunt for a word processor application that has a better backup feature than wordpad, doesn't stink for accessibility (looking at you, Libre Office), and doesn't have Google tentacles in it.