Well, I can see two things that might be happening :
1.- 50 mg Zinc (you don't specify mg's but I'm guessing) without adding copper is a very bad decision. You should have 1 mg copper for each 8-15 mg's of Zinc (there's not much consensus or a fixed rule about it) and don't have them at the same time because they will compete for absorption. Or you can get a formula (Jarrow makes one) that has both Zinc and Copper in forms that won't compete for absorption.
2.- Taking Iodine without magnessium PLUS Vitamin D without magnessium. Double magnessium deficiency. You should start taking some magnesium citrate/glycinate, minimum 400mg.