Why do nightmares exist?

There are many things that can cause nightmares, like stress, pain killers and other medication, or even just the position you sleep in. Generally, nightmares seem to be worse when you don't give your brain and your body some rest before actually going to bed. Depression can definitely make nightmares worse. If the nightmares started so suddenly, it is likely something came up in your life 2 weeks ago, something changed. Try giving yourself some more time to calm down before you go to bed. Put away your laptop and your phone and maybe grab a magazine, or just lay down on your bed with the lights off. Do something that calms you down. If that doesn't help, maybe consider talking to someone about what's going on in your life and get it out of your system. Good luck :)

We have nightmares to rationalize our fear for things, you may be less scared of something in real life if you have seen it before in a non-reality environment.as for them going away try these:1. Find a happy place, a book, or maybe a favorite TV show, something that you think of as the opposite of fear, something that makes you feel safe.2.Try to think of the things in your nightmares as just that Nightmares, they can't hurt you in the real world, and If thay can, you aren't afraid because it's not real, it's a dream, just a nightmare.

Some scientists theorize that nightmares are our bodies way of preparing us for dangerous/scary/sad situations without putting us through danger.