Deplorable Working Conditions

I am a teacher. My school is very old and situated in a low income area. I've taught in this school for five years without any problems.

Recently though, my school has become a health hazard to myself and unborn son. There is evidence of some kind of rodent(s) in the building.

Whatever it is has eaten bagged food, left droppings on my media station, and has made messes in other classrooms as well.

Our principal claims we can't call in the professional exterminators until we see live proof that they exist in our building.

It's so frustrating because I have to continue to work until my son is born and nothing is being done.

I did have a little reassurance last night as I researched this topic, but is still disgusting and I'm having anxiety about having to teach among these conditions.