Issues with falling items/mobs. Issue picking up items.

Whenever an item is dropped from my inventory, dropped from killing a mob/breaking block, casting my fishing line, and mobs falling, they all fall slowly and laggy. The world is relatively new and not much is in it yet so I don't think that could be causing it. Nothing else is laggy around me. Only items or mobs falling to the ground. And when I try to pick up an item, it takes around 5 seconds to end up in my inventory. Edit: this only has happened on one of my worlds as of now. The rest are unaffected.