I'm sorry that you had a rough day. When everything just piles on, it can feel overwhelming. And I'll be honest, I'm livid on your behalf about the losing your pumping session! It's one thing to have a medical emergency where you can't pump. But babysitting? Uh no, not gonna fly. There needs to be something in place so if that happens again, there is backup for that 20-30 minutes.
And why are you pumping in a closet?!? Can we get you a nice space to pump?
I agree though, don't put too much stock in a game of telephone. Who knows what kind of day either one of those teachers was having. Unless it impacts you somehow (like, you get reported for, I don't know, having to do nursing things so slightly inconveniencing a teacher who needs to learn to suck it up?), try and forget it.
Many, many hugs!