I can't see my held items.

When I clicked on a sword that was in my inventory, I used to be able to see it in first person, but now, I can't. I am still able to pvp with swords and bows, but when I click on the item in my inventory, i can't see it. I didn't care at first, but I just realized that I can't see maps in front of me even when I click on them in my inventory. I tried going 3rd person to view the treasure map, but I still couldn't see the map. Please fix, thanks.