It could be a kind of french Mulholland Drive. The materials where there: the affections of the past, the psychological insight, the fiction inside the fiction, fantasies, memories...
A failed writer retakes her old dream to write a beautiful novel, but her lacks of inspiration block her... until she met an actress, who tells her about her troubles. Quickly Sibyl sees a paralelism with her past, about her frustrated love with a man that bring her a passion and then another trauma related with a son they had. Sibyl lost her literal aspirations and her love and in ten years she discovered herself having a life that is safe, with some client as therapist and a husband that gives her estability. But none of these are now valid items to her.
The materials, as I said are good, but by one side the dialogue is too melodramatic, sometimes the scenes turns cartoonish and melodrama doesn't fits very well with the tone of the film, a psychologial drama. The scenes are also too repetitive, once we understand her old past love was very passionate, we don't need three more scenes of kissing and stuff.
By other side, the other characters, aside form Sibyl, doesn't feel with depth, something is missing with all of them.
It's a pity, because the idea is very good. A lost opportunity.