The lack of a true core usually means a person thrives on spite and immaturity. They are very attention-seeking.
The problem with constantly seeking attention, is that often you get negative attention.
You must teach yourself when to pull back, when to stay quiet. You must know when to take time out in your life to ask yourself who you really are, if living for the spotlight is really worth forgetting who you really were to start out with.
No solid foundation when it comes to your personality to start out with means no stability in anything you choose to do. Your momentum feels as though it could last forever, but it won't.
No matter what means you choose to replenish it, be it drugs, sex, alcohol, adrenaline, gambling, even religion, it will always stall quickly. An addictive personality always fuels this need, this empty hunger that is never sated.
The calm has to come from within, or it will never stay.