I'm so sorry to hear of your trouble!
I have been suffering with PCS for a year and a half.
From all that I have read is try to slowly increase activity and slowly push yourself with mental activities. Since you have trouble writing, try to write a little each day, make sure you use music too. The biggest thing is keep challenging yourself every day to do a little more a little better.
Other than that, I have found no better answers and I am so sorry. I don't think I would even wish PCS on my enemies let alone people who are just trying to live life.
Good Luck!