I think you can need something so badly in certain times, even if you don't recognize that you're using it as a tool to pull yourself out of a darker spot, that you make yourself believe in it. Only after it's over, you no longer feel the need for the tool. You cling to it, because you've created belief within yourself. But after a while it stops feeling real.
I have to put an effort into being conscious of having faith, which probably translates into needing an effort to have faith in the first place. And I'm no longer certain that I need that.