What happened:

I was playing on my girlfriends world with her. She was AFK while I was building. Her game crashed and I was disconnected. Upon logging back in, my entire inventory was gone. Several stacks of building/crafting materials, all of my armor, an enchanted sword that I had just made, all my tools, etc. And my XP was reset to zero. 

What I expect to happen:

Game crashes, I relog, and all of my inventory stays intact or at least relatively current within the last few minutes or even hours of gameplay.