In case you are not just giving us the raspberry, I am going to take a wild stab in the dark and offer a pure Science fiction fantasy hypothesis…. You have the mutation. People with the mutation cannot take as much Iodine as people with the old fashioned kind of DNA. Mutated thyroids do not need as much Iodine as the old fashioned thyroid glands. And when you inundate them with it, they shut down from overwhelm. That is why your levels are getting lower. Thyroid is overwhelmed and shutting down. It is purely a guess. And I have no scientific training. Just hoping to lighten things up a little. Maybe I have gone too far.
Do you have calcium assimilation problems? Do you have a chronic cough?