Sorry, didn't mean to sound mysterious! At least in my experience, there is usually a reason why MG is worse, whether that is activity versus rest, drug versus disease, an undiagnosed condition, an overactive immune system, a kink in biochemistry, or whatever. For healthy people without disease, they can do anything, eat junk food, loose sleep, etc. and not be affected. But with those of us with a disease, even the slightest variation from "pampering" or the right diet or whatever will push our immune system to be worse.
That's why I thought a journal of your daily symptoms, along with activities, food, etc. might help. It may not, but it's worth a try. So is finding more help.
Annie