My Oregon red spotted had been acting odd after regurgitating some silverside.

He had gone through a shed a few days before when I fed him on Wednesday. He ate one more silver-side than he usually would and started acting weirdly (moving his head around oddly). I put him back in his tank assuming he had eaten to much and would throw up. When I checked on him 20 minutes later I found all of the silver side on top of one of his hides. He was fairly normal after that. On Friday I noticed that he was moving slowly and mostly sitting in the same place for hours. He also wouldn't bother to run away from me if a put my hand near him. After that, I cleaned out his cage and put him on paper towel so I could keep track of things better. Sunday morning he seemed the same, but an hour or so ago I woke up to him thrashing around. He stopped after winding up behind his water bowl. If I pick him up now he wont move his front half but will wrap his tail around my fingers.

Could it be a thiamine deficiency?