The game froze while I was playing, I couldn't get out of the game, PC was completely frozen, I closed it. I reopened it then reopened minecraft and when I came back in my world I was in a wall, couldn't move or get out, I died crushed by a wall it said, I respawned home just to see a trees' leaves in my house I built, part of my house has magically disappeared replaced by trees and dirt, diorite and cobblestone walls. I go outside, bunch of block got paste right beside each others where I had made my pond and garden (see pictures to understand), I went in creative mode to see around my house and everythings is not as it was before, mountains are cut as perfect straight walls of cobblestone, trees inside cobblestone, water NOT flowing at all, big walls appeared in my world as if a new one has been created on it. I am very not happy about this issue. Please write me back on what could have happened.