People do care. There is always someone that will miss you. That would be terrible sad about you dying.
Why you say nobody cares about you? When I'm bad I find myself going away from people, I feel rejected even they don't think like this. I guess I'm the one who makes myself rejected.
And about your family, do they know how you feel? I know my closest family would be devastated if I gone away. I know that they will blame themselves.