I knew someone this happened to, they had had what is termed a nervous breakdown. They were so mentally exhausted their brain shut off to everything. There have been times in my depressive episodes I simply dont want to talk. I cant. Others I read a colection of stories of people that had many different symptoms due to mental health: blindness, being unable to walk, forgetting how to play the piano when theyd done it for 20 yrs...you are not alone. Your mind is exhausted. You need to heal.