The DIAMONDS is missing!

I was playing like normal survival and got 8 diamonds and then I use 3 of them to make a diamond pickaxe.I make the diamond pickaxe for digging obsidian to make ennchanting table.While I was holding the pickaxe,the game was suddenly kicked me.Then I try loggin again and my pickaxe is gone! Firstly,I think it was Wi-Fi problem so I make another.After mining the obsidian and make enchanting table,the game suddenly kick me AGAIN! I hope this game can fix this bug as soon as possible.