Hi there...these are my own experiences of some differences between the two in case it helps. I had to write fast but hope you figure things out soon

Chronic fatigue was like a bunji jump – once I was down there was no way back up! I could wake at 7 a.m. get up go back to bed at 9.a.m. feeling like the day was over, get up again take another 3 hour nap in the day and then go to bed again at 7 p.m. CF was also accompanied with severe brain fog. I could not start a project or job in the house I was so fatigued. Had the same list of things to do at the end of the year as I had at the beginning. Nothing got done…..Mostly generalized weakness - rest did not help.

Myasthenic weakness on the other hand was more like a roller coaster – up and down up and down- fluctuating weakness both of a diurnal type (Feel great at night and first thing in the morning - but by 4.30 p.m. am not able to lift my arms or hold my body upright at the dinner table) and also fluctuating weakness during a single action where you can not finish the action you started (you start off with normal strength but run out of energy before the action is completed - like not being able to finish brushing the teeth, finish peeling an apple, finish sharpening a pencil, finish your sentence etc) It´s not common to have brain fog with MG. And rest does help ….weakness occurs usually in specific muscle sets and I can pinpoint exactly the sets that are affected with myasthenic weakness whereas previously it was impossible to identify weakness that precisely in chronic fatigue.