Maybe mine is slightly different, but it's a common recurring dream I have of unpreparedness and letting myself or others down. These dreams keep on happening periodically:
* In group project activities, I did jack nothing toward the end of the project, and everyone was relying on my part or else the entire group fails. [Side note in real life, I started out strong in a college team project but then faded over time, and a couple of my project partners called me out and I took it to heart even until now as a someone they considered to be a failure component of their team. They really gave me the scolding of a lifetime beyond nightmares.]
* I didn't do any homework for the entire semester and went to to final exam passing only if I ace the exam.