18 months ago I suddenly was struck with severe fatigue and weakness in my arms and legs and loss of balance. I was told at the time i was low in vitamin D. In July this yr I saw a Neurologist who did a brain scan and told me it was Gillian Barre Sydrom and sent me for physio which did nothing for me, after suffering chronicly with this I suddenly started last month with a high heart rate of 163bpm. I have had a heart monitor and all bloods checked and 24hr urine test. Everything has come back ok apart from my Thyroid was "borderline" with a T4 of 21.72 and T3 normal. I have been told it's anxiety and to take anti depressants which I am inclined to turn down, I don't feel this is the answer to my problems. I'm off work and using a walking stick with no medical reason they can give me. Does it sound like it could be Thyroid related?