I am sorry to hear that but I really think it was stress. I have seen it happen with small lizards before where they lose the function of their legs and just lay there and appear listless. The best thing you can do is leave them alone and maybe cover the cage most of the day so they do not see you.
as soon as i saw the pics i knew it wouldn't last long. my brother had one, and one day we found it dead with it's legs stretched out, as if it had died mid-jump. sorry for your loss.