She looked at him like her answer could be both yes and no, with all the torment of having no clear idea which. Yes- the reason she was upset had almost everything to do with Dean, except that he was gone. But that wasn't true, either. She was upset that he was gone, because he was always gone.
You don't want to be here, Dean.
She nearly broke when another memory flashed behind her eyes, her own voice in her head, talking to Dean. In her home. In their home. That she didn't remember moving in with him. She hugged herself tightly, and Lisa's eyes closed hard, dropping tears. When they opened again, they were on Sam, and her voice was shaky.
"I feel like I'm going crazy," she said, fully believing every word.