Any Iodine experts out there??

Hi im 43/m and recently started taking Lugos 5% iodine. It reads 6.25 and I try to take one drop a day. I also take Mag Citrate and selenium. Ive only been taking these for a week or so. Today I made the mistake of not taking the Selenium and magnesium and id say about 5-6 hours after I took the Iodine I got this weird feeling in my chest (could be what people call a palpitation, but not sure) then followed by chest tightness and shortness of breath. I thought I was having a heart attack. Got home and immediately took some magnesium and selenium and the pressure subsided mostly. When I take the Iodine I feel great. I kinda feel like my old self again, but now im scared to take it. I did see a post on here by "mumnz" but dont know if this person is still around or not. Anyway, just wondering if anyone has any advice on the subject or pointers as what I should do or where I should go. Thanks so much Tweet