Disappearing items?

I’ve played Minecraft forever, since Xbox 360 Edition and never have I experienced something so annoying. I already knew that dropped items eventually disappeared, but I noticed that when I die and go back to my stuff I find them all missing.

Not just a couple valuable things like my Enchanted Pickaxe and Enchanted Books, but also resources like Wood Planks and Cobblestone. Before you could lose your stuff and go back to the exact location and find them, but now they just completely vanish if you’re not fast enough.

Can someone at least tell me how much time is given before they disappear? Would be greatly appreciated and maybe this will help to manage my time when I panic to grab my loot again