Sometimes i can't mine or interact with the things

It's the second time that this problem happens... I'd already have uninstalled the game and reinstalled again, and i've created a new world with another name, and the same thing happend again. I start the game and everything i'ts okay, but in some moment this bug just start again. I'm breaking some normal rocks in the game and the rocks just stop to droping the rocks that normally drop and the game start to running faster and after that the game just stop and come back to some minutes before i have start to broke the rocks... I have losted my latest save game because this problem have started and after that my save game just disappeared from the load of singleplayer without reason even when it was in the file of .minecraft/saves. Someone can help me please? Because i really wanna play this game for so long time and i buy it recently...