Just please be really, really careful Eleanor. Having a piece of your thyroid removed can cause crazy swings in hormone levels, and can actually make things worse. You need to 1) Ask for your TSH, T3, and T4 levels to be taken. 2) Ask for a test to determine whether you have thyroid antibodies. 3) Ask for a thyroid ultrasound to determine why it is large and abnormal. 4) Ask what treatments are available and what the potential consequences of each treatment are (there are many options). If you have antibodies but no goiter (big bulge pushing on things that you seem to be describing) it is autoimmune thyroiditis. If you have the antibodies and the goiter it is called Hashimoto's. They are essentially the same thing. What you absolutely, under no circumstances, ever, ever, ever (!!) want is to have your thyroid swinging from low to high to low. It is impossible to treat when this happens because the treatment for high and low are different, and if you are high, take the treatment, and then swing low, take the treatment for that, swing high...well it is awful...I think you probably get the gist. It sounds like they will test for all of the things I mentioned above, but please make sure they do. It is really important to get the right treatment. Also, if you were normal before pregnancy, and now abnormal during pregnancy, you might want to wait it out, as it is very typical to have thyroid issues during pregnancy and post-partum.
Lastly, and maybe most importantly, right now thyroid issues are the latest fad - everybody thinks they have them - especially in the U.S. It makes me cringe because it makes it harder to get treated when you actually have thyroid disease. I always have to know what tests I have had done and what they mean to prevent new doctors (like my ObGyn in this case) from saying "yea yea thyroid whatever". I hope you don't have any issues, and that it is just a pregnancy thing, because they honestly suck... but your post struck me because it really sounds like there might be something there. Make sure you stay on top of this.