Abby,
your openness and honesty is wonderful! I can relate in so many ways. I have had life altering symptoms for 7 years(difficulty breathing and fatigue) but in the last two months I have had my first bouts with falling and extreme muscle weakness. I too had a moment of sudden recovery after I realized that some of the leg shuffling/ shaking, etc disappeared if I took a deep breath and focused. So I too was having what I think was stress reaction and I questioned whether I was experiencing psychosomatic issues. However, since then, I have had another "crash" and there is nothing I can do to will my weakness away,but I am now more careful to "check" myself to make sure that I am truly weak, and not just in the habit of shuffling or dragging my leg, or any number if other things. This has been helpful to me. My symptoms are very real, but when I was so scared my mind was so focused on my symptoms that I did have extra symptoms. That realization has helped me to be more confident in knowing for sure which symptoms are from physiological illness and which symptoms were stress related and could be controlled by getting my mind focused. I too was/am scared of getting a psychiatric diagnosis, but now I clearly know the difference and can with confidence push for the correct diagnosis if needed.
I feel deep grief for those who are not treated because of doctor's tendencies to think that anything they can't test for must be a mental disorder. For that reason I will never tell my doctor that some of my symptoms were stress related. I will not give her an easy way out of diagnosing my illness. However it is very useful to me personally to recognize the differences.