The real reason being overweight is bad for your health:

[BrotherIvan]

30. It's hard work but worth it to get treatment

Check out some of the resources on the internet to empower yourself. Doctors are no longer trained to diagnose and treat hypothyroidism. If you read a book by Mark Starr, Hypothyroidism Type 2: The Epidemic, he explains why the TSH test doesn't even measure your thyroid (TSH measures the "Thyroid Stimulating Hormone" which is an output of your pituitary gland, not how much hormone your thyroid is putting out) and why you can have "normal" tests and still be acutely hypothyroid.

I started reading these things to try to help my mother and it made me so damn mad. When I started dealing with her prescriptions, I found she had been taking Synthroid for years. I had taken her to a new, highly-touted endocrinologist for over a year who never said anything about it and did not test for it. Both of us didn't even know she was hypothyroid! The very high-priced doctor just rewrote the prescriptions from other doctors, said something inane for the two minutes in the office and billed the insurance company for a hefty fee. For the fifty doctors we visited over the course of five years, (which I always researched and tried to find the best in the Southern California area) I could say only about two were really good doctors. Doctors are for the most part prescription writing services. Some are woefully misinformed or incompetent. It is a lot of work to find good, appropriate care. Some people have much more luck with holistic or alternative doctors because they actually listen to you and care about bringing you to good health. They don't have the false crutch of pharmaceuticals and they can't order a million tests in order to perhaps land on a diagnosis because doctors no longer know how to diagnose properly, they just guess based on tests.

I wish you luck and hope your journey to getting help is not too difficult. It really is worth the effort. I wasn't able to help my mother in time, but I have spoken to many people who feel like they found a miracle once they started being treated correctly.