Laurelette - Thank you for returning to bring us up to date on your situation. I'd like to say that supplementing with selenium is perfectly okay because that's one of the components necessary for the production of thyroid hormones. Iodine, on the other hand, can be counter-productive in some cases of hypothyroidism.
You really should see your doctor and get some tests performed to determine if you have Hashimoto's prior to supplementing with iodine. Hashimoto's is an autoimmune condition in which the body determines that they thyroid is foreign and produces antibodies to destroy it. If one has Hashimoto's, taking iodine can make the autoimmune reaction much worse in the long run. You'll need to get thyroid antibody tests completed in order to confirm/rule out Hashimoto's. The tests you need are Thyroid Peroxidase Antibodies (TPOab) and Thyroglobulin Antibodies (TgAb). You need them both because some of us have one or the other and some have them both. If you only test for one but have the other, you could be misdiagnosed.
If you have Hashimoto's, thyroid function will slowly decline until your thyroid eventually produces nothing. You may be at that point, already... that's where I am and I'm totally dependent on my replacement thyroid hormones, which are needed to maintain several body processes, including metabolism, heart rate, body temperature and others.
For actual thyroid function tests, you need to insist on Free T4, Free T3, and TSH. Don't settle for just the TSH that many/most doctors want to order.
All of that said, if you're going to base your diet on calories, daily calorie needs should be calculated based on your current weight, height, and activity level. A 1200 diet may not be sufficient to provide adequate nutrients, at this point. Safe weight loss is 1-2 pounds/week. Losing more than that may not be safe and may make you more likely to regain if you slip off your eating pattern for even a few days.
MedHelp has a Thyroid Disorders community that you're welcome to join. We'd love to have you post your labs and other information there when you get them done. It can be accessed via the following link:
Good luck and I hope you'll keep us posted on your progress.