I had the worst nightmare ever, of a nightmare world?

The world was completely different to what it should be.

There were extremes of weather, not always nice like it usually is. Sometimes so bad it even killed people. Sometimes the actual ground would shake in random places and times, destroying buildings and killing more people.

The worst thing was that people could be hurt, both physically and mentally. Their bodies could break, and go through all degrees of pain, even blood leak out. Their emotions could be hurt horribly with as much pain, and people could change like the weather. But worst of all, people's lives could end! It was terrifying, and actually accepted as normal. But before that, they gradually turned into monsters that still looked like their former selves. Horrible..

There were these things people caught that made their bodies go crazy in a thousand different nightmarish ways almost too horrible to even say, and it was insane because mostly they were invisible things. These things also killed millions of people.

Their own bodies would eat them, their own hearts somehow attack them and maybe kill them, their brains turn against them and paralyze them, or sometimes make them insane or rob their identity. Any organ could just turn against its owner in some insidious way.

In fact I don't think there was one thing that COULDN'T go wrong with people.

People weren't happy, and didn't even know the purpose of life. They just existed, as some kind of slaves.

Some people deliberately killed people.

Worse, sometimes whole countries tried to kill other countries, with giant explosions and metal monsters of ground and air.

This was the worst nightmare I've ever had. What the hell could it mean?