Your story is exactly like a pianist I knew in college. She was on a full scholarship, but during the previous summer she got sick like you (I can’t remember what it was). She lost all of her musical cognition — there was no connection between her hands and her mind as far as playing went. I remember her absolute frustration and devastation as she said how she had been playing Chopin and the like but now she couldn’t even handle goofy little choral accompaniments — part of her scholarship was to play for various groups. The faculty of the school was less than understanding and gave her massive guilt trips because she wouldn’t surrender the money. I don’t know the exact end as I left the school, but I know she was a fighter and was determined to win. You will figure out a way to succeed, too, but don’t allow ANY negativity creep into your life. When those feelings of frustration start, treat yourself like a five year old and say “I am not going to let you talk to yourself this way!” and take a break. Good luck!