http://www.thyroid.ca/Articles/EngE10F.htmlTS

If you manage to get a decent doc to test your TF ask for TSH, FT4 FT3 rt3 and Thyroid antibodies, not to mention ferritin and b12 for a fuller picture, that way you know for sure that no underlying problem lurks. Many docs just test TSH which is pretty useless. You can then go to one of the sites up to date with these things and check it out. I know of a good 1 or 2.
lotsa luv

Dawnx