What's the difference between feeling sorry for someone and truly loving them, especially in the context of a relationship with a narcissist?

I wanted to be disconnected away from the world. And not just the world, but from my friends and family also. What should I do to cope with depression and trying to get away from the past that kills me the most?
How do you keep your dignity when people treat you like you are helpless?
What do you do when you realize in the middle of an argument that your opponent is wrong, but it's physically impossible to convince them otherwise?