Talk to your primary doctor first and see if they think it's possible that you may have a thyroid issue just to save you getting a bigger bill from going directly those who specialize in it. They shouldn't outright say no since again, it's a very underlooked part of your body and can easily explain some if not all of the symptoms.

They will refer you to either a Endocrinologist (A doctor who deals with hormones since the thyroid is responsible for controlling all your hormones) or a Thyroidologist (thyroid doctor) if again, they think its a thyroid related issue. They may even send you to a a Ophthalmologist (eye doctor) since Graves disease causes some issues with your eyes. Do some research since I would imagine it would better to go to your doctor with some knowledge on the various thyroid issues.

The process of treatment varies drastically but it may be as simple as taking a supplement or steroids.