I'm sorry.

I don't have any advice about the thyroid, other than I concur with getting a new OB doctor. What about seeing an RE?
I don't think that there's any reason to wait a year and a half of TTC when you've already been waiting for so long. 6 months of extra heartache is just unnecessary. I don't know why doctors would have a problem with doing testing if a patient wants it. I know for me I have no desire to try for a year (if I end up with fertility issues) before looking into the problem. I want to be pregnant NOW.
I don't see why a woman has to wait if she's willing to pay for the testing, so long as the doctor is getting compensated, what does he care whether it's supposedly too early or not?
Sorry getting on a rant there...I hope you can get a good proactive doc/OB who will be on your side, trying to help you get pregnant.