Sorry to hear you feel so unwell. I suffered massive cognitive problems and considered Hashimoto's Encephalitis whilst medicating T4 mono-therapy as had the seizures and light flashes in my head. I now medicate NDT and although feel well most of the time, horrid symptoms still return if I get over tired//emotional//run down.
NDT (like all thyroid meds) will only work well if fundamentals are in place and the ratio of T4:T3 (in NDT) doesn’t suit everybody. You have over-range T3 results on 12 hours of fasting when taking no meds, so I would say you are overmedicated and taking too much thyroid hormone replacement can be counterproductive. Also test results have their place but remember it is not the amount of thyroid hormone sloshing about in your blood stream but the amount that is actually working on an intracellular level.
FT4 is usually lower when medicating NDT and you have high T3 levels but if they aren’t able to cross the cellular membrane in order to have biological activity and work their magic, you will suffer hypothyroid symptoms. Thyroid receptor site defects can be caused by elevations in cortisol or homocysteine. (see below).
Thyroid hormones transport into the cell is energy dependent. Therefore, any condition associated with reduced production of the cellular energy (mitochondrial dysfunction) such as diabetes, obesity, anxiety, depression, fibromyalgia, physiologic stress and anxiety, inflammation and chronic illness, high cholesterol and triglyceride levels, blah, blah, blah ... (in fact everything associated with hypothyroidism.. ) .. will also be associated with reduced transportation of thyroid hormone into the cell, (whether medicated or not) despite normal (or elevated as in your case) thyroid hormone blood results.
If NDT is not “right” for someone, it can initiate a Hashi attack which may be why you have a tennis ball in your throat which is sore and your voice is low and hoarse. If your thyroid antibodies are elevated (putting your immune system into a state of high alert), if may be that the amount of NDT required to suppress the Hashi attack, exceeds that of the hormone amount actually required for replacement. In this instance you would need to reduce thyroid antibodies and a great book in understanding all of this is “The Root Cause” by Isabella Wentz.
Another reason why NDT is often not tolerated is nutrient and iron deficiencies and cortisol elevations or deficiencies. Iron is key for conversion of T4-T3 and low levels may also decrease deiodinase activity resulting in conversion to reverse T3 (rather than the active hormone). Although you have high T3 levels, this could be from over medicating and be unusable if RT3 were to be elevated.
A deficiency in Vit B12 is common in hypothyroidism and known to cause possible neurological concerns. Also Folate (B9) works with vitamin B12 to help create, develop and regenerate red blood cells and make iron work properly. It participates in the homocysteine metabolic cycle and adequate levels are required to keep this amino acid in check as high levels are considered a significant risk factor in disrupting thyroid metabolism (& also cardiovascular disease ),.
Sufficient cortisol levels are required for someone to tolerate thyroid hormone or may interfere with the HPA axis which in turn suppresses thyroid function and weakens the immune system, as is needed to receive T3 from the blood into the cells where it becomes active. Inadequate cortisol levels causes so many imbalances in other hormones, all of which are (indirectly) required for good thyroid hormone synthesis.
Reducing your NDT will help in lowering over range T3 levels and you may need to add a little T4 (Levo) to balance, and most importantly address all nutrient deficiencies. Thyroid hormones should be rested six weeks after meds dose adjustment. Because of the T3's (within NDT) rapidity of onset achieving a fast peak serum concentration, I found it useful in medicating doses split into three until T3 tolerance improved. Once adrenal health improved, I was able to reduce to multi dosing twice a day and still continue to do this.
You previously say your iron levels are low. Are you supplementing and if so with Vit C, which will aid absorption and help avoid constipation ? ? .... Have you had Vit B12, folate and Vit D tested ? ? … . My thyroid meds only work with optimal levels of everything and sups can bind to thyroid hormones making them unusable so take any two-four hours away from thyroid meds.
If things still weren't too improve after rectifying deficiencies above, you could look into sex hormones as elevated T3 can alter the balance resulting in elevated SBHG, which attracts free T3, also disabling it from entering the cells.