The parathyroid gland is different from you thyroid gland.
Thyroid dysfunction could cause tiredness, depression, and constipation as well as dry brittle hair and skin.
To check your thyroid it would be done with a blood test.
You doctor may have checked that, but you would have to ask them to make sure.
The Parathyroid gland maintains a balance between calcium and phoshporus by means of your parathyroid hormone.
If it wasn't working properly your blood calcium level would have been really high or low and not in the normal range ( which it was).
To check your parathyroid glands function your doctor would order a 24 hour urine collection.
I would be more concerned with your thyroid and if it hasn't been checked your doctor can easily check it for you with a simple blood test.
Let me know if you have more questions.