I can't get back my items after I die because they despawn instantly I got killed by a skeleton and I spawned back and my items were gone and I was in my house

Items take 5 minutes to despawn if they're being ticked (loaded/not too far from the player). If you think they despawned much faster than this then could you give us some more details on the conditions that made this happen? Otherwise this ticket will be closed as invalid.