Is it normal to not be able to remember anything during burnout?

I'm tired boss. I've had a really rough semester and I can't look at my calculus without my eyes glazing over. Now that it's time for the final I'm looking back at all the concepts I had "breakthrough" moments with... And I got nothing. Can't remember a lick. I don't have any gusto in me still, I'm already planning to retake the course but fuck me ive never experienced burnout like this.

Is this normal?