You know more than you think

The about statement is what I frequently tell myself when exam time comes around. Or when I have to face a challenge where my knowledge is both my tool and my fear igniter. I often don't feel I know anything at all. All the knowledge runs out of my head like water going down a tap. When I start to feel anxious that I am lacking in knowledge I tell myself that I do in fact know more than I think I do. Then I study, just to be on the safe side :)