Some put weight on with iodine, others loose weight. Unless serious hyper-symptoms like a racing heart and thoughts, I would continue the Iodine as long as it gives other benefits. Increase the selenium, take some lithium. Loads of magnesium.
Experiment by taking days off iodine, or a week.
My eldest son is skinny; this actually increased while he was on college without Iodine and co-supplements for a few months. Now after some supplementing again, at least the appetite is back, a little weight on.
Libido will come back when the body has what it needs; other issues more important for it; at least my experience:)