That feeling.
I keep having this recurring dream that I realize late in the semester that I've not been attending one of my classes. The class is some sort of calculus spinoff, and taught by one of my current professors, only it's not really the professor, it's his/her evil counterpart. It takes place in my old high school, but it's a college level course. In the dream, I know that I attended this class for the first week, then somehow decided that it wasn't worth my time, so skipped it once, and then forgot to go back. And of course the day I do show up, the professor is giving a test, which apparently is a regular occurence I would have known about had I attended the class.
And I hate this dream. I hate that feeling I get from time to time where I feel like I've forgotten to do something but can't pinpoint it. I got that feeling over the weekend when my mom mentioned that Friday was November 5th. And I spent the next 20 minutes trying to figure out why I knew I was supposed to do something on Nov. 5th. Never did figure it out.