This happens to me so often. I find myself in a situation where I don't remember putting myself into, or a long period of time seems to shorten.
It also happens at class; whilst some classes seem to last for days, others feel like they last a couple of minutes and I remember nothing. Sometimes I also realize that my homework has been properly done and the answers are alright, but I don't understand the procedure or, in Math/Physics, it doesn't follow my usual patterns of problem-solving.
Tom