if they met with you before ..was that meeting after a health issue? or something else?
if your dr notes states you can work without limitations then that is it. the absence should be covered I imagine..
do you have a union? take a rep

if you have a friend in the company take them with you if you feel comfortable and they allow it.

they might just want to know if you are physically able to perform your job without limitations and if not what restrictions might be needed and your dr note said no limitations so just say that...but then you need to stick to that.