i believe it was newport who said that lead will make you constipated.
thats what i meant by a trigger, its not he Iodine itself, but perhaps some secondary result of taking the Iodine that uncovered or exposed you to something pre-existing. i hope you are hydrating well.
my bowels got reconditioned using lower bowel balance from the barefoot herbalist. eight months on that and i have never had a problem since. check it out.