Do you have to get a doctor's note to be exempt from gym stuff in highschool in the state of iowa because of a fear?

Im asking here because no where else would let me also because I don't know where else to post it basically my teacher made me get a doctor's note stating that I have automontophonia the fear of anything humanoid so I didn't have to do CPR and now I'm worried I might have to get another because I'm afraid of flying objects like gym balls.....