Unable to collect cobblestone after a while

I've been playing this world for a while now and I have been able to collect cobblestone just fine, but suddenly whenever I destroy a block, it's not going into my inventory. I have tried a wooden, stone and iron pickaxe, but none of them have worked. I have closed the program down and started it up again, and it let me play normally for about 10 minutes, but then started again.

Does anyone know how to fix this?

Solution 1:

From looking at the exstensive discussion in the comments, it has appeared as though you had doTileDrops set to false. Change this by entering in /gamerule doTileDrops true. Hope this helps!

Solution 2:

If you mine stone with a pickaxe you will get cobblestone. If you mine stone with a silk touch enchanted pickaxe, you will get stone.

Try clearing out you entire inventory except for a pickaxe, go mine some stone and see what you get, if you get cobblestone then that's normal. If you get nothing THEN there's an issue. In order to get stone it can either be created in a furnace or mined using a silk touch enchanted pickaxe.

EDIT: Try 1. Creating a new world 2. Restarting your computer 3. Send the command /gamerule doTileDrops true