Disappearance of inventory

I was playing minecraft 1.17.10, i was in the end and when i go back to the portal to overworld, i died with no reason and lost all my inventory, the message or notice of my death was:"Fany Coco01 has felt from a high place" and i spawned in my bed with nothing in my inventory and no experience. I don't know why this happened, i tried again go back to the portal to overworld, i lost nothing and i didn't died.