The Lonely House by Marie Belloc Lowndes

It may have been an hour later when suddenly Lily Fairfield sat up in bed. In a moment she knew where she was, and yet she did not really feel awake. She told herself with a feeling of fear that she was asleep-asleep, as she had been asleep that night ten days ago, when she had started walking in her sleep, so frightening greatly Uncle Tom.

Something now seemed to be impelling her, almost ordering her, to get up and to begin walking through the silent, sleeping house. She fought against the impulse, the almost command; but it was as if a stronger will than her own was forcing her to get out of the low, old-fashioned Empire bed.