Flying Water And Leaves After Installing Addon

I Installed An Addon And My 3 Years Old World Is Started Bugs. I Disabled And Removed The Addon But Dont Worked. I Cant Uninstall Minecraft Because I Has Got A 3 Years Old World. When I Am İn Forest Or Mountains There is Found Flying Leaves. I am broking they and they generating again after restarting the game. And There is found flying waters to sea or river. Please Help Me!!!