The first thing to know is that “thyroid problems” can be broken down into two different categories, based on the way the gland is malfunctioning:

1. Hyperthyroidism means it’s producing too much thyroid hormone.
2. Hypothyroidism means it’s not producing enough thyroid hormone. 

Hyperthyroidism can sometimes be a sign of an autoimmune disorder called Graves’ disease. Similarly, hypothyroidism can sometimes be a sign of an autoimmune disorder called Hashimoto’s disease. But whether it’s due to one of those conditions or something else entirely, any glandular dysfunction can cause symptoms if it’s severe enough.

Excessive fatigue is considered a sign of both hyper- and hypothyroidism. But each condition also has its own set of symptoms.