Not able to mine

I am hitting the stone over and over again and nothing is happening, i have tried hitting stone in different places and still nothing. If i tab out and back in it then loads and breaks the stone and gives me the stone. It's as if its server lag but i'm playing singleplayer.

The problem is now fixed as far as i can tell it was due to steam downloading updates for other games in the background, once i paused it the game worked as normal. But anyway as for the animation it would just crack then go back to normal then crack again but not actually break.