Hi Debbie,
Losing one's intellectual capacity is far harder than losing an arm or stuttering or any other physical symptom because it is an assault on one's sense of self.
I know how painful it is. I suffered a brain injury and my neuro-psych revealed that my IQ had nose dived - and missed the water. Like you, I felt stunned and sad and wanted my old brain back. I still cry sometimes, but I know I can't ever go back, so I'm doing my best to maximize and maintain what I have left.
As the others have said, it's really important for you to get as much rest as possible. I'm doing cognitive therapy and there is a
big difference between my performance on rested versus tired days.
This really is a traumatic thing to go through. I hope you won't ever hesitate to reach out here on the forum or seek professional or pastoral help if you feel you need it. You're not alone.
Tale Care