Memory being overlapped by a dream?

This really weird thing happened to me once. It was the first day of class in my senior year of high school and I was a few minutes late. The teacher had just got done calling out roll as I walked in and he asked me for my name. What I remember happening is everyone in the class (most of whom did know me) calling out my name simultaneously, the teacher than marked me present and I sat down.

I don't remember thinking how strange it was at all. I do remember thinking, "Ha, I'm so popular." It is obvious that this never actually happened, but it is the only way I remember it. I asked a friend in the class about it, but he didn't remember that happening, of course. I think if it did then it would be pretty memorable.

So what I think happened is that I had a dream that took over my memory. In the dream, I was popular and everyone knew my name and was excited to see me in their class. Its like saving a file with the same name as a preexisting file - it just overwrites it. So if no one actually told the teacher my name, then what happened? Did I tell him my name myself? Did something really embarrassing happen that I don't want to know about?

Has something like this ever happened to any of y'all?

You remembered a dream you forgot, that is so similar to reality, you thought it was a memory of waking life. This has happened to me dozens or even hundreds of times.

This has also happened to me more times than I can count, expecially when I was a kid. And just like WakingNomad said, it was most likely a recalled dream.

The brain function involved in REM sleep is responsible for the extreme vividity; and a dream that is closer to reality than absurdity [like yours] will even further confuse the distinction between dreaming and waking experience. Especially when it's a dream you forgot having in the first place.

The scene with Jason T. Hodge in Waking Life explains it pretty well.

Don't feel bad. For years I remembered a ton of what I thought were really elaborate movies/books from my childhood, only to find out later they were really dreams I had.