You are starting with the premise that we are created. So if we are created beings then we must have a purpose either corporately or individually. I cannot believe a created being has a purpose unto himself. Why would he?
I am not sure it follows that if we are created we have to have been created for a purpose. God could have created us on a whim with no purpose in mind, except perhaps to pass the time.
I believe we were created for a purpose (and I acknowledge that is a matter of faith). The purpose was to love and worship God, of our own free will.