Similar to a midlife crisis, midschool crisis is when midterms or finals in school are coming up and you're having a mental breakdown. You start getting frantic because your grades depend on how well you do on finals! You even stay home all weekend and study. Basically you won't have a life until finals/midterms are done.
Me: I'm so stressed out! Midterms are tomorrow and I haven't studied at all! I'm having a midschool crisis!
Friend: Oh. That sucks. :(