I agree with the posters above. A double life is no life at all, but it is also very telling to me that you feel it is something you want to do. To me that means your current life is not emotionally satisfying to you?
Find a therapist to talk to, figure out what YOU want. Make it happen at an early age in life and you'll be happier in the long run.
Sitting around and making up fantasies that are impossible might help whatever you're feeling a little bit right now but it is not a way of living a life and being fulfilled OR happy.