Guys i really messed up, i fell into the void in the end and I had all my good tools with me, I left before i died so i haven't lost my items yet. How the hell do I save myself. (I'm playing on 1.14.1)
The gamerules are kept somewhere in the level.dat file, I think (I'm probably wrong and it's in some other file). You can change them without having Minecraft open at all using an NBT editor such as NBTExplorer. Keep in mind that the values and property labels you see in the editor won't necessarily coincide with the values you'd see from within game, but most of the time you should be able to figure things out easily enough. When in doubt, make a new world and go looking in that world's data before messing around with your "keeper" worlds.