Well-meaning doctors examine you, and listen to you talk about your symptoms... the symptoms that make you absolutely miserable. Unexplained weight gain, brain fog, depression, exhaustion... Your hair is thinning (and you might not realize this, but your cells are starving!)
You are prescribed antidepressants, sleep aids, and menopause hormones, which may or may not help to mask the symptoms.
It may never occur to your physician that the underlying cause of all of these is hypothyroidism.
Most doctors only do one type of test for thyroid disease, and that test "misses the boat" more often than you might think!