First of all, Im sorry to hear of what you are experiencing and I can imagine how scary it all must feel to lose strength/muscles shaking each time they are strained. Until you get a firm diagnosis of anything from qualified doctors, I understand its easier said than done, but worrying will not change anything in your body. Anxiety will just worsen the symptoms. Now I have a few questions:
1) Have you had any massively stressful/traumatic events in your life in the last year?
2) Have you had any significant head or spinal injuries recently?
3) Have you had crab or excessive sea food in your diet in the last 1-5 years?
4) Is there any work/environment related toxicity (any workplace hazards) that you may be exposed to? (chemicals etc).
5) Do you have any sleep disturbances?
6) Do you have any breathing disturbances?
7) Has the situation plateaued/flattened since you last gave us an update or does it worsen each day?
Thanks