When your temperature is 37.5C during the day (99.5F), your thyroid isn't blocked. Or if it is, maybe you have a fever that needs to be investigated. Regardless, since you believe that 500 MCG (not MG) of Iodine is tormenting you, then stop taking it. The only thing I can imagine is if you are getting this Iodine from seaweed/kelp, there might be an intolerance issue if you're low in copper. But we don't recommend using Iodine from seaweed anyway.
[Note: this detail about a relationship between kelp and copper is remembered from a long time ago and would need to be verified before being taken seriously.]