Lost a Water Stone

[Pologanso]

Hi,

Today, I was levelling my Shelder and when its level was ok, I decided to evolve it in a Cloyster, so it held a Water Stone, I level up him. Ok, it evolve and I disconnected. But when I reconnected it was a shelder again, lost its level, and lost its water stone. It was not in my backpack and i don't know where it is, it disappear and i don't know if it's possible for anyone to do something for me.

 

Sorry for my bad english.

Thanks for your help