seeing an Endocrinologist! They deal with thyroid issues and other of the endocrine glands see the attached site:
http://www.endocrineweb.com/
The whole endo system IS complex and it does affect neuro issues?
So both docs should work together to find your problems, especially at such a young age.

And, obviously? SOMETHING IS GOING ON! Just never lose faith that someone CAN find the cause or a treatment to help you!
I suspect that you will be subjected to a full battery of tests! Mostly blood tests for starters - LOTS OF BLOOD being drawn..so before you see the doc the first time? Drink lots of water the day before and time the day of so you don't have to interrupt your meeting w/the doc to 'go'. Later mite come MRI's, sonograms and other tests? Most of these are not invasive, but are used to 'eliminate' a heap of possible problems.
For now? Keep your cool, have faith in your self that something's not rite and stick to your guns! Please keep us up to date on how you're doing? Just don't write SCARED on your Tee-Shirt when you go in! Rather think that TOUGH is on it and go from there! 's - j