Crafting Table and Furnace glitch. Can't get any crafted items.

I played on a survival game for about two days, when suddenly my crafting table and furnace glitch. This happens on every survival game I play. What happens: I go to craft something, and when I craft it, it shows I used the materials to craft it, but it doesn't show up in my inventory or whatever its called. So I back out of the crafting screen, and see the item I tried to craft floating in the air, like I mined it out of the game. So I go to pick it up, and it doesn't let me pick it up. Same thing with the furnace. I smelt something, it shows I used the materials, but when i back out of the furnace screen, it shows the items floating around the furnace, but I cant pick them up... It is very annoying, and would very much like to know what is going on.