Much of this may not apply to you as each body is so different, but here is my story.
While trying to conceive with our first, I stopped getting my period. I waited 3 months, kept testing and it was not positive for pregnancy. A trip to my primary doctory indicated hypothyroidism. We medicated w/Synthroid to bring my levels into the normal range. I also had some ovarian cysts due to not completing my cycle for 3 months, so they induced a period to clean things out. (I was also referred to an OB/GYN that tried to diagnose my cysts as PCOS when I had no other indications of that condition, a second opinion agreed with me).
Even after starting the Synthroid and inducing a period, I still was not completing a cycle. I ended up doing 3 rounds of Clomid. On the 3rd round, with ovary monitoring by ultrasound and a boost of hcg to release an egg, we conceived and carried a healthy baby to term. We conceived a second and third baby with no extra "help" (besides ovulation detection kits). Baby number 2 arrived healthy and full term and I'm 31 weeks along with baby number 3. My OB checks my thyroid every trimester to ensure that my levels are normal. During pregnancy number 2, we had to increase my dose for a bit, then reduced it later, after delivery.
Bottom line: it is possible to maintain a pregnancy (assuming no other issues) and have a healthy baby as long as your hypothroidism is being treated properly. My levels are kept in the 2.5-3 range. I never saw an endocrinologist, but I'm sure it would not hurt, they are the experts.
A side note (and sorry for all the TMI, just trying to be helpful) do you know if/when you're ovulating? I bought some inexpensive test strips through http://www.early-pregnancy-tests.com/ I have no affiliation with this company. I bought a whole bunch of tests and counted myself lucky if I ended up giving them away to a friend if I didn't need them all. I ovulate late (day 18) so if you may have to go through an entire cycle of testing before you find your approximate day.
Best wishes!