Lost items in multiplayers.

I play in my friends world,and I got many items and experience.And I also went a way far from the spawnpoint.The game crashed in the midway.I join the world again but all of my items disappeared.And I spawn on the world spawnpoint.I try to join again,but it still happens.

I don't know why,may I died but I didn't see death interface or death message,and my friends don't know either