Going through the nether portal. As the overworld was generating, my character was somewhat in a wall or suffocating in blocks after it has finished generating. I spawned back to see all of my items have not dropped near the portal in the overworld nor in the nether. I was really confused because there were no enemies nearby that could've attacked me or anything else. I'm not sure if this is a rare occurrence but I had a decent amount of stuff and items that I carried with me and they all just disappeared after I suffocated in a wall.