First, I want to say I'm so sorry you're experiencing this. I experienced something like this years ago when I was in a teaching residency and I know exactly what you mean about the massive spikes in stress and anxiety.

Second, I want to say that if your distress is so severe that it's causing you to consider taking leave from work, then definitely speak to someone at work and if they won't listen try to get leave approved. As others have said, expect that this would be unpaid under almost every circumstance.

Third, what is your teaching title/role, how long have you been in it, and are you trying to move to another school for next year and beyond?

Wishing all the best and I hope you can find a tenable solution ASAP.