Why am I not getting anything when I break blocks?

If I were to take a guess at the problem it may be because you have gamerule /gamerule doTileDrops false set to false. You can check this by typing /gamerule doTileDrops and hitting enter, this will tell you if it's set to true or false. If it says false simply type (true) after the previous command (This is assuming you are using command/cheats)

You said that you were in creative mode.

In creative mode when you break blocks they will not drop an item because you can get the item from your creative inventory.