@Tella
I'd like to encourage you NOT listen to much to opinions of "professionals" when it comes to "using your brain & ME/CFS".
I am the living proof that cognition in ME can actually IMPROVE when cutting back light,communication and noise for a LOONG time.Don't worry,I mean it.
I believed the "use it or loose it"-idea.It had dramatic consequences for me and that I am here now,after being very severe for 2 yrs, can read and type is a miracle! thanks God!
Please consider"less is more".It can be healing.
Trust your body/brain.If it doesn't want to read it means its too much for you at the moment and would probably do more harm.Doctors always make the mistake that they compare or brains with healthy brains.