Final answer:
Nancy most likely woke from Stage 1 sleep, which is a light phase of sleep from which people can be easily awakened without feeling like they had been deeply asleep.
Step-by-step explanation:
If Nancy felt as if she wasn't even sleeping when she was nudged awake, it is most likely that she was in Stage 1 sleep. Stage 1 sleep is a light sleep from which a person can be easily awakened. In contrast, waking from REM sleep, which is characterized by dreaming and muscle paralysis, would often leave a person feeling groggy and more definitively asleep. Night terrors and narcolepsy are also inconsistent with Nancy's experience, as night terrors result in panic and are generally not remembered, and narcolepsy involves irresistibly falling asleep rather than waking feeling unrested.