I've been through all sorts of craziness with my thryoid in the last 18 months.
At that time, I gained 20 pounds out of no where and my hair started to fall out. My fatigue was worsening! I know from my readings that these were thyroid symptoms. I went to one doctor, who told me my thyroid was fine.
However, I went to a 2nd doctor, who told me that my thyroid was "off," and in fact I was hypothyroid. It doesn't take much to cause havoc.
It's a long story, but check out a medication called Thyrolar (similar to Armour mentioned above). You might want to read books by Mary Shoman...she has a lot of information on the topic.

IN addition to getting on medication, I started to explore and change my vitamin intake. One major change I made was take a B50 tablet and additional B12. I also started using a gentle/non detergent shampoo and a top notch leave in hair conditioner.

Very recently, my doctor has added a very low dose Iodine supplement for me to take.

I lost all the weight, have more energy and my hair is back to normal! I am very grateful for my doctor!!! My advice is that if you are not satisfied with your medication or doctor, make sure you get a second opinion.