Dreams aren’t a straight map from symbols to meanings for all people. They’re in code, and the dreamer should try to feel out what it means for them.
I’m not sure I’ve had that exact dream but I’ve had some close ones, and I know of some people having had such dreams.
Again, dreams are personal. If it were my dream, I would look/think/feel for what the school context means and feels like it is about to me, and then bathrooms, and then poopy unusable bathrooms.
Sometimes something like that seems to mean I actually need to go to the bathroom…
But for me, bathrooms tend to involve something about social issues, and whether I feel like I have what I need or not, and how I relate to my community. Often in my dreams bathrooms come with issues about privacy and usability and embarrassment, and for me tend to be about messy social situations.