teen- seems to me you have the concept of the difference between believing and knowing. We believe that Hashem created the world and runs it at every moment-…”m’chadesh b’chol yom…”etc. In order to know something you have to see it-and since we are human and bound by time and space we can’t know Hashem, we have to believe in Him. Two more points. In order to say that something doesn’t exist, one has to know everything in the world that does exist in order to make that claim. Since we are human, we can’t know everything that does exist in the universe, and therefore can not make a legitimate claim against G-d running the world every second.
The other point is, that believing is a choice, and being a Torah Jew an obligation. That being said, believing is a healthy spiritual choice that will bring a person to act a certain way. Not believing is also a choice that will bring a person to act a different way. Believing ultimately has no bearing on the existance of things. It is there to help us be better, and make wise choices, and trascendental moves.