Most folks need to have their adrenals functioning before they can do thyroid hormone supplementation. It's a bad catch 22 - the thyroid hormones support the adrenals but not if they are failing, then they drag the thyroid down.
The Iodine may be supporting the thyroid but the hormones may be causing a bad reaction on the adrenals. I took adrenal cortex extract for a couple of years to heal my adrenals. I used Enzymatic Therapies Adrenergize but many people use Isocort.