If I learned, suddenly and definitively, that nothing is moral and nothing is right, I wouldn't change anything except to be more secretive about my own morality in order to keep everyone else from finding out that they don't need to follow theirs.

I'm not so sure of that myself. There are cases where I want others to realize that they don't need to follow their own morality. Sometimes people's morality leads them to do things that harm me. (I'm sure you can think of examples.)