You're probably right. If it had been a work day I probably would've woken up in the nick of time.I dunno if that is fortunate. I think you subconsciously knew it was your day off.
I used to get that with my old radio alarm clock. A terrible way to start the day.I had a radio one once and I was forever getting deja vu concerning the news where'd I'd been listening to it in my sleep without knowing lol
MW