Most doctors only check TSH. You need to also check TPO antibodies (which would confirm Hashimoto's--I have it). When I was first diagnosed, my hair was falling out in clumps and I'd gained almost a stone in a month, which is odd for me.
It's now been four years since diagnosis, and I take Naturethroid, which is NDT and not a synthetic like Levo. You have to be a huge advocate for your health with thyroid issues. Taking a pill rarely gets you back into a good spot. I also take:
Turmeric
Selenium
Iron
Vitamin D3
Vitamin C
A sleeping pill, as early rising (tied to poor adrenals) was killing me
I haven't eaten gluten for four years, no grains for two, and keep refined sugar to a minimum
I work out four times a week, raise two small children, walk my dogs, have an active social life, and am preparing to return to work within the next six months. When my thyroid starts to veer into hypo range during the cold months, I up my dose a little, take lots of D3 and eat more good fats. Feeling mostly good can be done, but it's hard. For starters, check out a website called Stop the Thyroid Madness.