I was diagnosed with low thyroid in July of 05 after my MD ran so...

I was diagnosed with low thyroid in July of 05 after my MD ran some blood work due to a rash and fever. Prior to that, I had no symptoms of hypothyroidism and in fact am a competitive triathlete and road cyclist. MD put me on Levothyroxine and even though my levels came down, I noticed no changes in energy, metabolism, etc. In October, I began having extreme headaches accompanied with numbness and tingling. MD refered me to a neurologist and after numerous, expensive tests, everything came back negative. Blamed it on anxiety and stress. I blame it on this drug. I feel worse now while my levels are normal?, then I did when they were originally diagnosed as being too high. What's the benefits of this drug if it makes you feel like crap? How can so many of us have these same side effects with not response from our doctors?