Iodine can cause the hyper symptoms if you take too much, when you first start taking it. One is to start slow and gradually increase over a period of weeks. I could barely tolerate a drop when I started, now I take 8 drops a day ( 5% Lugol's) If you don't take the supporting minerals with it it can make you hypo too.
"The Jod-Basedow effect (also Jod-Basedow syndrome and Jod-Basedow phenomenon) is hyperthyroidism following administration of iodine or iodide, either as a dietary supplement or as contrast medium.
This phenomenon is thus iodine-induced hyperthyroidism, typically presenting in a patient with endemic goiter (due to iodine deficiency), who relocate to an iodine-abundant geographical area. People who have Graves disease, toxic multinodular goiter, or various types of thyroid adenoma are also at risk of Jod-Basedow effect when they ingest extra iodine. The Jod-Basedow effect also been seen as a side effect of administration of the iodine-containing contrast agents, or amiodarone, an antiarrhythmic drug.
The Jod-Basedow effect does not occur in persons with normal thyroid glands who ingest extra iodine in any form."
- Wikipedia - Jod-Basedow phenomenon
I'm not sure what your actual question is...
Do you have results of thyroid hormone tests that you could post so we can see what your actual hormone levels were when you were hyper, hypo and now, when you're back to normal? Be sure to post reference ranges with all results since ranges vary lab to lab and have to come from your own reports.
Also not sure what your "high dose of Vitamin CD is"... What dose of iodine did you take and for how long?
Have you been tested for autoimmune thyroid conditions... Graves Disease and Hashimoto's? Graves Disease is "always" associated with hyperthyroidism and Hashimoto's is associated with hypothyroidism, but often characterized by periods of hyperthyroidism in the beginning and can "flip flop" from hyper to hypo and back to normal many times before finally settling on permanent hypo... Hashimoto's is the most common cause of hypothyroidism in the developed world. Many of us, here on the forum, have Hashimoto's.
Have you had a thyroid ultrasound to determine if you have nodules on your thyroid? Nodules are common with, both, Graves and Hashimoto's.