The thing is in the moment when you feel completely empty inside, it's hard to describe, but there's this point where you start feeling like everything that exists would be so much better without you being a part of it. Looking at it from the flip side and seeing what I couldn't before, it's because we don't see ourselves as part of the whole and necessary to the fabric of existence. How do we fix it? Surrender and have faith in something; love, humanity, friendship, honestly it doesn't matter what the thing you find to have that faith in is, because it's all about love in the end. The feeling of separation is a feeling of non existence and being unlovable. It's an ego based viewpoint of ourselves and not real in any way. It's a manifested false belief that is so destructive to a person and everyone that cares about them. People just need to learn how to be more receptive and accepting of each other and stop hurting each other.