This happened to one of my coworkers: he just lost an hour of time at work, like it was just completely gone from his awareness. I don't know how it resolved, but I know he had to take a bit of sick leave to get it checked out. He seems to be doing fine now, though.

At any rate, sorry. I used to fall asleep in physics class all the time, and I know how inconvenient that was without deeper medical concerns. Wishing you well~