Game gets SUPER glitchy after playing for a while

Whenever I play in a world for over 15 minutes, or I switch maps, the game goes insanely wonky. The examples I have are from a server world, but even when I'm playing offline the same issue occurs. I also have a texture pack, but even with the pack completely removed from my computer, the issue remains... When this happens, there are a lot of repeated blocks, and sometimes things start moving about even when I'm totally still. Thanks for aring and setting up a bug submission page!