Many people spend their whole lives asking themselves the very same question. The sadest part is, they never find the answer.
Most people, don't even decide what they want to do for a living until their mid 20's. Most people don't even realise they need to take care of their health until they reach 30.
Seems to me, once you get a grasp on who you're NOT, you'll see who you are. Who you are is what you're about. It's your character that is the defining definition of who you are. It's not your clothes, your taste in music, your favorite color, the car you drive, or the culture you relate to.
So, maybe, you should ask yourself, "What is my character?" "What do I stand for?"
The rest of the world feels the need to find an identity, and I guess I've been through that too. You seem to be the type that follows their own path regardless of outside suggestions, or the supposed "norm" society has set for us to follow. That's a great thing!