Dreaming

Where are the other rooms coming from? I must have seen them before. I must have. I keep on having this dream of an apartment, my apartment, where I have been before in my mind. When I wake up, I question the validity of the dream and wonder if the familiarity is just from this dream or have I seen it before? I won't draw it if I do, it might interfere with my previously assumed mental image of this space.