"Well hey," Derek says with a dry laugh, shrugging his shoulders helplessly and flicking some water at Thomas. "Awhile back, I had a whole month or two straight of days I couldn't handle it, and I spent most of them on four paws. So at least I have that."

He doesn't tell Thomas why, that it was because Stiles dumped him and he just couldn't stand being so close
to his scent and his heartbeat, that it was driving him crazy. Then Stiles came and asked Derek to take him back, and he had a few good weeks before he disappeared. Then his heartbeat and his scent, they were gone.

"It's okay to have those days," Derek assures him, standing up a little straighter so that his shoulders are out of the water. "Just don't let them own you."