World problems

Put the summary of the bug you're having here
My world doesn't load my items, and my Minecraft crash when i load a world or join a LAN world. My skin don't loads too.

What I expected to happen was...:
My items, my skin, and all the resources load normality

What actually happened was...:
My world doesn't load my items, and my Minecraft crash when i load a world or join a LAN world. My skin don't loads too.

Steps to Reproduce:
1. I click in Multiplayer or Singleplayer
2. I load the world or join a LAN world
3. BAM! my skin and my items don't load! Is as if I was entering the world for the first time, and as if I had not an account. Thanks for attention. I am Brazilian, so I do not notice if I have a word wrong.