Do you have gaps in your memory?

My daughter (whose just finishing kindergarten) asks a lot of questions about when we (my wife and I) were in school.

So, recently I was recounting all my teachers to her from kindergarten through high school. Strangely, when I got to middle school (7th and 8th grade), I could only remember one teacher’s name (out of about 12 teachers).

What’s more, I remember very few details about the entire academic experience. Classes I took, other students, what the inside of the building looked like. I can barely recall any of it.

Meanwhile, my memory of grade school and high school is crystal clear.

personally, this was a very rough time for me – so it may be related

Have you experienced similar gaps in memory?
What do you think causes this?