Until 2003, the "normal" range of TSH was 0.5 to 5.0 or 5.5. You will find that a lot of labs still
use this range. However in 2003 the American Society of Endocrinologists recommended that the
normal TSH range be narrowed to 0.3 to 3.0. And actually a lot of people feel better when their
TSH is below 1.0. So, my personal opinion is that your doctor is treating you correctly because
you have hypothyroid symptoms and a TSH of 3.74.
For some people the Synthroid can cause those hyperthyroid symptoms that you are worried about
but it is a fairly normal dose that he is starting you on. I have seen some doctors recommend slowly
increasing the dosage. They recommend starting with a quarter dose and staying on that for a week
to ten day and then increasing by a quarter each time. You could ask your doctor if he recommends
that. Also, I don't know if you have Hashimoto's thyroiditis which is a common cause of hypothyroidism.
The only reason I bring that up is that it can cause fluctuating levels of thyroid hormones being released
because your thyroid gland is inflamed. So often, or at least in my case, I feel symptoms of hypo at times
and then it will change to hyper. Good luck, I think once you get on the right dosage of medication, you
should feel a lot better.