really suggest you have a technicium uptake scan.
Self medicating iodine is not a good idea. I had fairly normal blood tests,
but a goiter, and also some severe signs pointing to thyroid issues.
My antibodies for Hashimoto's were negative.

The radioactive scan showed a very damaged gland. And the upshot was
the assumption that the hormone being made was not bioactive, so even
though my tests were not extremely off, I was pretty bad.

On hormone now, and much much better.
Some general signs:
1) orange discoloration of the skin, most noticeable on palms and feet.
(low thyroid prevents conversion of betacarotene to Vit A...so it is deposited in the skin)

2) hair falling out. Hair on arms and legs disappearing.

3) cold feet --numb feet..painful feet. Carpal tunnel in hands.

4) brittle nails--that break easily.

5) low fasting glucose (blood sugar)..mine was 60-70 ave. After hormone, they are in the 90 range now.

6) swelling of neck/face. My whole face changed when I went on hormone, and people I knew for years, didn't recognize me at meetings!!
7) TSH above 3.0. (new levels)

Of course there may be other signs, but I really don't think taking iodine, beyond what is in a multivitamin is wise. You should have a doctor supervise that.