Sarah is Disinterested

He watched her. She normally moved like...well, the tremendous manipulative flirt she was. Now she was moving casually down the hall, stopping at her locker, then continuing on. "Sarah...are you all right?" "What? Yes, why?" She asked, neutrally. "No reason. You just seem different." She shrugged. "I guess." She seemed to yawn. "Thanks for asking. I'm fine." She continued down the hall. Jon frowned. He'd seen that attitude before on some kids, mostly quiet solitary types. But Sarah was one of the most outgoing people in school. *What was going on?*