This question should be the kind that one asks himself and not necessarily demand to get answers from others.
The truth is most people cannot pull off a rational answer as to why they are on earth. They still struggle to find the balance.
Let's be clear about this. The fact that you are doing something and seem so good at it doesn't mean that you were created to be doing just that. No. that would be wrong.
The fact remains though that everyone was created to fulfill a purpose. There's a wealth of potential in everyone and it is the discovery that should be the focus.
There's this quote I heard some time ago that has stuck with me:
"Problem exists wherever men exists but in the right perspective, every man is the solution to another man's problem"
The sad reality is that many people never really discover their purpose. Fulfillment in life is rarely possible if one doesn't work in line with purpose.
Purpose is that one thing we do and find fulfillment doing. It's that one thing that comes easy with us. We don not struggle to get it done. We get angry when others don't do it well.
I think i'm a writer. I find joy writing. I don't struggle to put a piece together. I get irritated when I see a badly written piece.