Disappearing diamonds

Was mining in a single world and mined 10 diamonds Took them up to my storage chess place them in with my previous three I had found from a previous cave, so there was a total of 13 diamonds in my chest after getting supplies and going back down and exploring more I came back up to add two more diamonds to my store and the previous 10 were gone that I had played there and just the two that were previously. Double checked both of my chest that were in my base and also the chest that were in the mind shafts that I had been exploring, and nothing was there, nor was the diamond or blocks that I had mined previously

Was mining in a single world and mined 10 diamonds Took them up to my storage chess place them in with my previous 2 I had found from a previous cave, so there was a total of 13 diamonds in my chest after getting supplies and going back down and exploring more I came back up to add two more diamonds to my store and the previous 10 were gone that I had placed there and just the two that were previously. Double checked both of my chest that were in my base and also the chest that were in the mind shafts that I had been exploring, and nothing was there, nor was the diamond or blocks that I had mined previously