I got up at 6 AM. Got dressed. Had some breakfast. And then I drove to the school. A usual morning.
I was not expected. The teacher that I was scheduled to sub for had not left lesson plans (and this teacher always leaves lesson plans). I knew what was coming.
This is one of my biggest fears any day that I sub. The dreaded "Sub? What sub? I don't need a sub." I was sent in error.
This has happened to me quite a bit. If I find no lesson plans from a teacher, I don't assume that the teacher neglected to leave them. I assume that the teacher is going to show up any minute and be startled by my being in his/her room. A couple times the teacher did show up to tell me the lesson plans since he/she was going to be on campus (chaperoning a field trip, going to an on campus meeting, or carpooling to a meeting with teachers), but that's the exception rather than the rule.
I called the sub caller. She got her dates mixed up. I wasn't needed, so I went home. (And I was so rattled that I left with classroom keys. I turned around and went back to return them.)
I suppose if I wasn't so paranoid about this, it would happen less frequently. It's just one of those things. People make mistakes. I get caught in the middle of them.
(Oh, and Mercury is retrograde, so this sort of thing is to be expected.)