Error: NONE

I was bored one day, so I switched on Minecraft (my internet was out so I was bored.) I created a singleplayer world and loaded in. I started chopping down trees, like any other player wood, (haha, see what I did there?) anyways, I started to build my house, and the first few days were normal. I got some iron, reached bedrock, went to the nether, but one day in the nether while exploring I found a sign that said "(none)". I tried breaking it, but then my game crashed. I logged back in the world, and I was at my house at my bed and with none of my armor or items. I got my backup items, and went back to the nether to get my good items. What I found there was odd, I didn't see my items where I died, instead, I saw them a few hundred blocks away from where I died. I also noticed there were no mobs nearby, Ghast, Pigmen. etc. I found the whole thing odd and creepy so I went back to the overworld. It was night when I got back, but 20 minutes later it was still night. I entered my base and saw another "(none)" sign. I thought maybe it was a joke by Mojang at this point, so I shook it off and didn't break it. I went underground and started mining in an unexplored cave. It was at this point that I was hearing blocks being broken and steps all around me and it was getting louder. I tried running out of the cave but on my way out I saw smoke. I didn't see it but my mine noticed it and I eventually noticed it. There was no smoke next time I went down. When I got back to my base, something was VERY wrong. I saw the grass for my base all the way at the bottom, and my base was At the bottom of the world. I turned around and saw glitched spruce trees, they were upside down? I went further and further into the forest trying to run, and then I saw it. A figure in the distance. It had blue eyes, blond hair, and looked like a typical girl skin on Minecraft. There was no nametag over the head. The entity started to punch trees, when I realized that everything in the world now looked how it looked like before. I was watching this entity as it chopped the same trees as I did, it built the same exact house as I did. It mined the exact same tunnel, punched the same (none) sign as I did, and crashed. ran through the same tunnel I did. And when it found the entity, it looked different. It had a black skin, like Null, but with red eyes. The person ran to the entity and then my game crashed. Afterwards, I went and deleted the world I was on. I was thinking about the strange occurrence today, and decided to write this page.