You need some additional testing even before seeing the Endo. And by the way, being an Endo does not guarantee a good thyroid doctor. Most specialize in diabetes, not thyroid. And most have the "Immaculate TSH Belief, by which they think that a TSH test reveals all that is necessary for a potential thyroid patient. Wrong.
You should always insist on being tested for the active thyroid hormones, Free T4 and free T3 every time you go for tests. The only time TSH is useful for diagnosis is when it is at extreme levels. I expect that your low TSH has resulted in low FT4 and FT3, but that needs to be confirmed. In addition you need to be tested for Vitamin D, which is very important, B12 and you were tested for ferritin, which needs to be 100, so yours is terribly low.Low ferritin (iron) can also cause symptoms, some of which mimic hypothyroidism.
Even more important than test results, it is vital to know about your symptoms. Please review the following list of symptoms typical of hypothyroidism and tell us which ones you have.
Increased sensitivity to cold (low body temp)
Constipation Have to take laxatives or fiber)
Dry skin (Need to use skin creme)
Weight gain not explained by diet or exercise
Elevated blood cholesterol level
Muscle aches, tenderness and stiffness
Pain, stiffness or swelling in your joints
Heavier than normal or irregular menstrual periods
Slowed heart rate
Enlarged thyroid gland (goiter)
There is much to discuss, but let's start with this.