You can struggle with all difficulties, physical or mental.

Contending with something is different from beating it, and much more available. You can contend all day at low volume: taking the medication, turning up to the appointment, refusing to let the thing make your decisions for you.

Bodies and minds both respond to that kind of stubbornness, though never on a schedule anyone can publish in advance.

Whatever sort of difficulty you have got, one that shows on a scan or one that does not, you are already doing this. You did it to get as far into today as you have.