I am definitely filling it with something. Sometimes it happens that I am doing that with buying new objects or so, but other times I am just doing something. I would go for a walk, ride my bike, drive a bit, listen to music, write a post on Steemit or answer a few questions in here. There is always something to do to fill that emptiness. I also think that it is mind created and somehow we are searching for it sometimes. It doesn't fall from the sky. It has some positive effects if used properly. If you have often times this type of feelings and you set to always do something when it comes you will find yourself doing things that you haven't regularly done. Like cleaning your house more often, talking to someone close to you more often or working on something that might happen to be a long run project. Sometimes it helps to just observe it also and see that it actually has no foundation and it's just mind created but not all of the time and with anyone. In most of the cases physical action is the best solution.