Lexi, I am reading Dr. Brownstein's book currently and came across something that might be pertinent to your issue.
In addition to what you stated you were taking, were you also taking Vitamin B2 and B3?
Brownstein wrote about a case in which a patient did not really feel better until they added B2 and B3 to their regimen in addition to 75mg of Iodine daily.
Brownstein gave them 100mg of B2 two times daily and 500mg of B3 two times daily and the patient felt a lot better.
Apparently, in some people there is a defect of the oxidation/organification system with iodine. The Iodide in Lugol's must be oxidized to Iodine inside the cell. If this doesn't happen properly, the H2O2 (Hydrogen-Peroxid) can damage the surrounding tissue, leading to autoimmune attack. B2 and B3 (along with selenium and the iodinated lipids) regulate the oxidation/organification process and reduce the autoimmune response.
If you haven't been taking B2 and B3, I would suggest trying 100mg of B2 two times per day and 500mg of B3 two times per day to see how it affects you. They are water soluble so no worries about an overdose.