Are u still there? I would be extremely interested in talking with you as I have simlar symptoms. I can tell you the tests I have had so far and where I am at in diagnosis. But for the meantime, I would insist on a high and low contrast mri on the pituitry gland.
Cortisol is an adrenal hormone and does not determine hyper or hypo in relation to the thyroid.
Yes, your TSH of 5 is high - the new standard (recommended 8 yrs ago) is 3.0 for the high end of TSH, but a lot of labs/doctors still go by old numbers, usually 5 for the high end.
Your FT4 seems low, but we would need a reference range to know for sure, since reference ranges are lab specific and must come from your own report.
I can't answer about the "weird/rare" issues - a lot of times just getting thyroid levels under control, tends to alleviate the symptoms.
I must admit that I'm not real familiar with the growth hormone issue, except that I know our levels tend to decline somewhere around the age of 19-21 (or thereabouts), and continue to decline as we age. I think this is normal; I guess because we aren't growing any more? Mine were low too, but at my age, I didn't really figure I wanted to grow much more (unless I could grow upwards, rather than outwards.......lol)....except in a mental/learning capacity.
From my understanding, there are only rare occasions in which a fully grown adult would need additional growth hormone.
Sometimes, we tend to look more to the rare, unlikely things, rather than those that should be explored first.......
Have you been tested for thyroid antibodies? For hypo symptoms, you would want Thyroid Peroxidase antibodies (TPOab) and Thyrogobulin antibodies (TGab); for hyper symptoms, you would want Thyroid Stimulating Immunoglobulins (TSI).
Those tests would confirm/rule out autoimmne thyroid diseases - either Hashimoto's Thyroiditis (hypo) or Graves Disease (hyper) - both cause the antibodies to attack and eventually destroy the thyroid, but they don't work the same way.
You might also want to get your vitamin B12 and vitamin D levels tested. I have pernicious anemia (B12 deficiency), which causes a lot of symptoms also -- mainly fatigue/energy levels, tingling/numbness in the hands, feet, legs, abnormally sized (enlarged) red blood cells, etc. I self inject vitamin B12 every 2 weeks; does wonders for the energy levels........
If it's any comfort, a lot of us gave up many years to diseases that were not diagnosed properly. We've had to fight our way back to health, and even at that, we have our occasional set backs. The idea is to learn as much as we can about whatever disease we have, then fight for the treatment we need.
I, personally, have Hashimoto's Thyroiditis/ hypothyroidism.......it was a long road to diagnosis (I suspect 20+ yrs) and it's been a long road back to something resembling what I might consider "normal" for my age; actually maybe even better than normal for my age....