Minecraft crashing when i'm mining

My Minecraft crashes always after I mine some blocks, or sometimes I open the world and the first block I try to mine, the game closes, and when I open the world again, I lost some itens (like my armor) and the world lost some Megabytes. Yesterday, when I start to play, the world was with 40Megabytes, and after 4 crashs trying to get diamonds with a diamong pickaxe, the world was with only 30Megabytes.

It was this way since the last version. I searched in various sites and here on Mojang and I can't find the fix.

 

The print was 2 minutos ago, when I try to prove the bug again.