It was strange, Sam acting the way he had been for a few months. He'd become more and more quiet and broody than usual, and you'd noticed his odd behaviour more and more. You'd mentioned it to Dean, who'd been watching his brother carefully, but he'd insisted that Sam was fine, he just needed space to figure out whatever was going on in his head.

"Hey you okay...?"

Sam looked up at you quickly, caught off guard by you asking the question. He didn't think it was that noticeable, the fact he'd become more withdrawn, more distant and quiet.

"Yeah," he nods, but you didn't believe his answer for a second, and he knew it. He offered you a smile, but it doesn't reach his eyes, "Yeah. I'm just fine, no need to worry."

He doesn't want to worry you, he doesn't want you to get concerned for him or anything, it's just a silly slump. And he'll get out of it.