Have you read the book by Dr. Brownstein called "Overcoming Thyroid Disorders"? Well, I've just basically started it, and I'm pretty slow reading it because have to read over stuff. But this book may help you and help you understand about the T4 and T3 issue. Also important is the salt loading. You might be sick from not having enough salt and water. Anyway, I would sure read this if you get a chance. Some people are poor T4 converters into T3. T3 is the active form, which helps your metabolism and other things. But your T4 can appear normal, then your T3 might be low. There is a lot to this stuff.
I would also make sure that you've read his book on iodine. I may reread sections of that as well.
Hope that you get better. The salt/water/iodine will help get the toxins out of your body, although it won't happen overnight.