It probably would not hurt to see an endocrinologist and have some blood work done. I can understand that you don't want to pay the high fees, but, sometimes, a doctor is the only way to find out what is wrong.
If you had thyroid issues they'd put you on a thyroid therapy drug and then place you off it to see if the body can compensate for itself. I recommend talking to an endocrinologist about your thyroid issues and getting blood's taken
Go to a doctor and have a full blood count done as well as a physical examination and other things.