That's nothing. I used to do worse.
One time I spent hours thinking it was evening on a Sunday. I found it curious McD's was only serving breakfast... at dinner time. And why the streets were nearly empty. Or why church had already started. And why my parents weren't at work.
It wasnt until I asked someone at church that it became clear.
I've slept 24 hours straight and missed an entire day off.
Probably more if I could remember.
Getting days mixed up is pretty common.