I agree with estrelinha and if your doctor doesn't want to work with you find a good Reproductive Endocrinologist.
Have you tested for thyroid antibodies? TPO and anti-Tg., If you have positive antibodies, TSH higher then 3 for months,symptoms and you want to be pregnant, yes I think you should try a low dose of levothyroxin and retest your TSH in 4-6 weeks (talk to your doctor about this, ask for thyroid antibodies)
A more background... I was tested the first time because of symptoms. Mostly being really tired all the time. As in the first thing I think about when I wake up in the morning is when I will be able to go back to sleep that night, and despite a pretty honest effort to lose weight I have only been able to lose about 30lb in the past year and a half. I also have cold sensitivity, but the other common symptoms do not really apply.