I hope this is your cycle! I'm a teacher too and my teammates were curious when I had my monitoring appointments because I'm never gone. I just told them I appreciated their concern and didn't elaborate.
It is so tough being a teacher! I am like you, NEVER out. And when I am, everyone knows something is up. At my old school, people were so nosy. I have to say, everyone at my new school is understanding & they don't ask too many questions.