I tried to adress my hypo thyroid with kelp, for months; it did not work. Cold hands and feet, and a very low body temp.
A possibility that the kelp triggered your hypo T to get even worse; as the small amount of Iodine in a kelp pill is hardly enough to supply the thyroid, then you have the other tissues that need some. Female breasts need approx 5 mg daily, just to keep them healthy/ without FBD, lumps, pain. Been there too.
Men can go for a little less, if healthy.