Like Shelly, it was my GYN who discovered my thyroid problem! She felt my glands thyroid and realized it was enlarged. I ended up having thyroid cancer and had a total thyroidectamy, but prior to having it removed I was yo-yoing between hyper and hypo thyroidism and I gained about 20 lbs(and this was my freshman year of college, so people kept trying to tell me it was my freshman 15 but I knew I wasn't eating that poorly!!).
I have now been on synthroid for the past 4 years, maybe a little longer. It did take my body almost a year to get evened out weight wise, and I do get tired still every once in a while.
Feel free to ask any questions, I will do my best to help with answers!