I've never turned my Kindle off. Duh, guess I thought "sleeping" was off. Haven't had any battery problems so far. When I remember, I keep wireless off.
But after your comments, I wanted to read what the manual had to say, and if you're like me, when you want specific instructions, it's easier to search on the computer than on the Kindle itself. So after I read your comments about turning off, etc., I went to my computer to see what the manual had to say. My Kindle for PC wouldn't open. Nor my Kindle for PC2 (laptop). The Kindle itself seems to be working.
Sent an email to Amazon support and they sent back saying "we need to talk more," with a link for them to call me back, so now after a good night's sleep, I'll tackle that one.
I'm thinking maybe it was those blasted Windows updates that come along every now and then. Or maybe when I renwed my Norton and they had to get on my computers by remote.