How Do I Know For Sure That I Have Thyroid Disease?

I suffered from hyperthyroidism. I would have never known but I got to a point where I had the shakes all the time like I wasn't eating. The thing is I was eating as much as I could get my hands on. I ate four dozen Christmas cookies at a time and drove my wife crazy. (I don't know if it was because she had to keep making more or because I wasn't gaining any weight.) I lost so much weight (260 down to 210 in a month and a half) I started to worry that something really serious was going on. I went to the V.A. Hospital and the Endocrinologist walked into the room and just looked at me and knew I had a problem because of the enlargement in my neck. Please do yourself a favor and have this checked out ASAP.

Judging from your symptoms I think it wise for you to make an appointment with an Internist. "A doctor with a PA after his name. Preferably a gastrointerologist. Sounds like you have an intestinal problem. Ie; Bloating, hair loss, constipation. I believe your body isn't able to absorb all the nutrients from the food you are eating. Hyperthyroidism causes you to lose weight rapidly as DundalkTom mentioned and Hypothyroidism makes you feel tired and causes excessive weight gain even if you are not overeating. If you don't find a doctor who figures out your health problems then be very persistent and go to as many doctors as it takes for you to find the right diagnosis. Take action ASAP.

Because of the numerous complaints and problems you're having a doctor visit is definitely the best idea.

The "norms" for thyroid hormone levels are very broad, and don't really show "normal" thyroid function for sure. One way to check if your thyroid is functioning as it should be is to check your temperature often, and if it is usually lower than 37 degrees Celsius then there is a good chance your thyroid glands need some help (try Kelp capsules or seaweed foods such as sushi).

Malfunctioning of thyroid gland has hundreds of symptoms and every patient does not show all, so the better idea would be to get a complete blood scan and a thyroid test for a confirmation.

A thyroid function test will give a definitive answer as to whether its working or not. There's obviously some other reason for your symptoms, so you should keep on at your dr until you get an answer.