It is VERY important to salt load, take vitamin C and Bs, magnesium and selenium together with iodine; and in your case also zinc. This is the bare minimum!
Seems like you have started the detox wagon (flu like feeling), and if your body lacks one of these supporters it can be a tough ride.
All elements need to be in the right form too; real salt, magnesium in the form of malate or citrate, selenium as methionine etc. please read before you continue iodine; //www.curezone.org/faq/c.asp?a=13,281,2962
In the cases I have worked with, me included, it was always a lack of other supporting minerals that was the problem when symptoms like yours occured (heart, breathing.) When corrected the symptoms went away in a matter of days.