Answer:
herself, a prisoner of her own existence.
Explanation:
In this narrative, the narrator is depressed following the birth of her kid, and her psychiatrist husband diagnoses her with hysteria, advises rest, and rents a rural cottage. So, in this extract, she calls herself "the lady behind", a stranger in her own body, her own existence. Behind the pattern, she moves. She recognizes her because she is that lady, but she does not recognize her as a character.