Terrain loading problems / terrain corruption after reloading world

Don't know what happened to my world, but after just a leaving and rejoining the lobby caused my whole world to corrupt. The corruptions were that there were more than 4 holes that seem to be entire chunks. Also, I think after the game glitched and I became unable to pick things up, the entire world started corrupting. There were also problems regarding terrain loading. These are extremely urgent bugs, so I hope these can be fixed as soon as possible. If you are wondering what my world looks like right now, here are some screenshots: (I did not mine/clear these blocks deliberately)