Minecraft Low Quality

So I was playing with my friend, we were bored so we downloaded an addon. It was a really cool one! It was the black hole addon and then after that, my Minecraft started acting strange. My Minecraft quality. I will apply a screenshot of my realm world to show you the decrease in quality. I deleted the addon, nothing. I restarted Minecraft and my computer TWICE, nothing. I even uninstalled Minecraft and reinstalled it and nothing. By the way, I have a good computer, running Minecraft at 60 FPS at minimum.