I always had nightmares when attending college that I am given an exam for which I a completely not prepared for.

Well, one day I get to class, the professor goes "clear up your desks".......my heart sinks as I mostly was an 'A' student and really cared about my grades. I take the test, I don't remember any of this stuff as I missed some days due to illness. I completely flop the test. When giving it back to my professor, I straight up told him....hey so this is pretty embarrassing, I completely forgot we are taking this test, I was completely unprepared. I told him it felt like nightmares I had, and felt surreal. He had a pretty good laugh and told me, that if it affects my final grade in a significant way he will allow me to take another test.

I did get an A in the course and that test was irrelevant in the grand scheme of things.