The unreliable narrator in The Woman Upstairs?

Just read a a bit further in Claire Messud's The Woman Upstairs and now, let's see, narrator, Nora, goes to the Somerville studio she (supposedly) shares with Sharina (?), a concept artist, to find a party/photo shoot in full swing as S. prepares for a big exhibition in Paris - S. seemingly manic herself consults with Nora about various aspects of her installation project - an interactive "wonderland" based on the novel - eventually Nora goes to sleep wakes up and the entire mess has been cleaned up. Hm - would one maybe think that there was never a party at all, just a long fantasy in which a world-famous artist flatters this would-be artist and ambitious amateur by seeking her advice and help and praising her pedestrian if skillful work to the skies? I hold to my theory - this is a classic "unreliable narrator" and she will end up narrating this story from a hospital ward or at advice of therapist (a la Portnoy, Zeno, et al.)