Sounds to me that your endo is being proactive, which is a good thing after reading some of the posts from people out here! Utahmomma explained it very well. If nothing else, they will have a baseline so they can watch for any changes.
Good luck!
an ultrasound is a good next step. Many doctors would just jump to meds without getting a good visual of what your thyroid may be doing. An ultrasound will look for enlargement, misplacement, and nodules. It's a safe test that will tell an endo much more than just labs alone.