Day Dreaming. Reality vs. Reality.

I have this dream, this wish, to do something meaningful and important for the world. I know I have it in me, I know there's something I'm supposed to do, I just can't figure it out. It is because of this that I've always looked toward careers that involve helping people like a doctor or a psychiatrist, but do I want to do these things for a living? There is this fire inside of me, this ambition, I don't think I could sit in an office all day for the rest of my life. I need excitement in my life, danger. After realizing that I want to travel, experience differnt people, experience different cultures, learn different languages, I feel lost, like there is no place in this world for me. Perhaps I could work for national geographic, perhaps I could join the peace corp, perhaps perhaps perhaps. I want to do everything, I want to be everyone. So...what do I do?