where did my UV layout go?!?

Here is the .blend file in question:

i had it all mapped out the way i wanted it. I then started using that object as an obstacle for some fluid simulations. Once i finished that, i rendered and everything with an image texture was gone. I checked my UV layout and could find nothing, as if the entire layout had been deleted. Also, i tried to un-wrap everything again but it would not let me until I un-pinned (alt+P) all the vertices in the UV editor. only i never pined anything in the first place. At least not intentional.