Iodine for cats

I'm feeling guilty. I put a drop of Iodine in my cat's water bowl. It's with the stuff with one drop equaling 75 mcgs. I looked it up and apparently cats require (according to vets association) .1 mcgs per day.

I've also been giving my cat distilled water in her bowl for the past month.

She's been rather lethargic lately and I'm wondering if this change has adversely affected her.

It could also be the weather since it's in the 90s but still.

It's going to be tap water for her until she improves.