I have similar problems with motivation and haven't found a real solution but I'd like to share something someone told me recently that struck a chord.

"If you had a broken leg, you wouldn't beat yourself up for not being able to climb a mountain." So remember what you are facing is difficult and it's ok if you need to reevaluate goals. It's not healthy to hold yourself to the same standard as if you didn't have these problems.

Because of my upbringing (and societal stigma at large) I really beat myself up about not being able to have enough "grit" to deal with my problems. And that discussion really opened my mind to the idea that it's ok to take a step back when I need to. What is manageable everyday can change and that is OK.