"Reality" is only determined by our perception of the world. If you perceive the waking world as being more of a reality than your dreams (which you probably should), then the waking world is your reality. No one's requiring you to change anything about your philosophical views on reality, life, death, anything like that (although they are probably asking you to think outside the box - question not the usual, but the unusual).

Besides, I have LDs just fine without having to ask myself: "What if this world is just the dream and my LDs are real?" or something far-fetched like that.