In some cases the "emptiness" that you are describing is similar to being chronically lonely. Not lonely as in amount of people around (one can be lonely even in a huge group of people), but lonely in a way that one needs a very good friend to be around. But even then, the feeling may persist depending on the circumstances.
As MIH said, it is something that doesn't really go away. You wake up with it, and live out your day with it, doing nothing but merely "existing" without joy. It is a rather bleak existance at that, and many times those people just want to be loved and appreciated.