With the low TSH and low Free T3, the indication may be Central or Secondary hypothyroidism...Central hypothyroidism is when there's a problem with the pituitary gland in which there isn't enough TSH to stimulate the thyroid to produce adequate thyroid hormones.
Could you please check the reference range for the Free T3 also? The one you have listed is very different from what we, typically, see.
Are these the first thyroid tests you've ever had done? If you have previous ones, it would be interesting to see what they might have been, if they weren't too long ago, just for comparison.
Even though you're taking a B-12 supplement, there's no guarantee that absorption is adequate to keep levels high enough to prevent numbness/tingling in the hands and feet. I have Pernicious Anemia which is an autoimmune condition in which one doesn't absorb vitamin B-12 via the stomach, so in spite of the fact that I took supplements and ate B-12 rich foods, I was deficient for years and it was never caught. Therefore, I have permanent damage to the nerves in my feet caused by long-standing B-12 deficiency. In addition, some people are unable to convert the common form of B-12, cyanocobalamin, to the usable form, methylcobalamin, so it's important to buy the right type, as well.
I also have insulin resistance/impaired fasting glucose, but have not experienced further nerve damage because of it.
Just to add, elevated glucose excretes more magnesium through the urine causing symptoms of low magnesium. And the list of magnesium deficiency symptoms below is not in the least a complete list in the least (I know as I had severe magnesium deficiency from combined insulin resistance/impaired glucose tolerance, high doses of vitamin D and surgery). To reverse my insulin resistance I removed all refined sugar from my diet (I don't eat a lot of carbs otherwise). I also can recommend exercising and intermittent fasting (I prefer the leangains method).
Excerpt from Best Magnesium Citrate - How to Fix Heart Palpitations or Irregular Heart Beat...
"It has been found that 4 out of 5 people in the US (or 80%) are deficient in magnesium. If you are experiencing 2 or 3 of the following symptoms, you probably are one of them.
- heart palpitations, heart arrhythmias
- chest tightness
- urinary spasms
- menstrual cramps, premenstrual irritability
- difficulty swallowing, a feeling of a lump in the throat
- light sensitivity, loud noise sensitivity
- high blood pressure
- numbness, tingling, zips, zaps and other vibratory sensations
- being uptight or prone to temper
- muscle twitches, soreness, cramps, spasms, tension, tightness
- back aches, neck pain
- headaches, migraines
- jaw joint problems
- needing to sigh a lot, unable to take a deep breath
- leg spasms, charlie horses, restless leg syndrome
- anxiety, panic attacks
Excerpt from Wikipedia's Hypercholesterolemia (high cholesterol)...
"Hypercholesterolemia is typically due to a combination of environmental and genetic factors. Environmental factors include obesity, diet, and stress.
A number of other conditions can also increase cholesterol levels including diabetes mellitus type 2, obesity, alcohol, monoclonal gammopathy, dialysis, nephrotic syndrome, hypothyroidism, Cushing’s syndrome, anorexia nervosa, medications (thiazide diuretics, ciclosporin, glucocorticoids, beta blockers, retinoic acid)."
The most common cause of small fibre peripheral neuropathy listed is diabetes or glucose intolerance.
I have permanent nerve damage from B12 deficiency and insulin resistance/impaired glucose tolerance. I've never had abnormal fasting glucose levels but my glucose went too high however after I drank a glass of glucose (2 hour oral glucose tolerance test - OGTT) which showed I had impaired glucose tolerance.
In regards to hypothyroidism, my neurological symptoms (which are not permanent for me when I have the right amount of thyroid hormone) includes burning feet, pain when applying pressure to the soles of my feet, tingling/numbness in extremities, carpal tunnel, absent reflexes, cerebellar ataxia, severe bradypnea (central nervous system depression).
Have you thought about checking your Vitamin B12 levels. Low B12 can cause neuropathy in the extremities of hands/fingers and feet/toes.
Your thyroid labs actually look pretty good. I am a bit surprised by the suppressed TSH with about perfect Free T4, your Free T3 levels at 33% of the range is actually a bit low. which again makes me suspicious as to why the TSH is suppressed.
Do you have any other thyroid related symptoms?