This EXACT thing happened to me a few months ago. I was terrified!!
I went in to get a gyn. exam at my normal gp, a routine thing. She felt my neck and said I had an enlarged thyroid and ordered me to have bloodwork and an ultrasound.
I was scared, and since this wasnt something I had anxiety about, I was even more convinced it was a "real" problem this time.
Guess what? My thyroid scan came back normal. My blood work came back normal. I spent over a week convinced I had thyroid cancer. All for nothing!
Boy do I wish I had that week back where I did nothing but look up thyroid cancer online.
Even if there IS somethin wrong with your thyroid, there is good news. 98% of thyroid cancers are completely treatable. Its the most treatable cancer there is. Also, up to 50% of the population has thyroid nodules (most unnoticed...these are documented during autopsies and thats how they figure this large amount has them), and only 2% of these are cancerous. So....even if you do have lumps and bumps, its more than likely not cancer anyways. And if it is, you can be treated.
I honestly wouldn't worry about it. When I finally got my results I was so annoyed. But, doctors can never be too careful and we should be thankful for that. At least they are doing their job.
Take care and if you have any more concerns pop by the thyroid board, you will see how little there is to worry about.