I had a similar experience. And I still have them...but I don't make it public.
I have similar dreams to the ones you are experiencing...however I do not wake up with a nosebleed. I wake up in tears.
The dreams you are talking about may or may not be what people call 'supernatural'. Personally I do not believe in the supernatural in it's literal sense...but I do believe there are things that the human brain has not yet discovered. Telling the future, seeing into it, past lives, ghosts, aliens. These are not supernatural in the literal sense of the word...we are just unknown to them right now...however they may be very natural.
I have had lots and lots of disturbing dreams...but a little different to yours. Your dreams seem more literal. Like things that would happen in everyday life ( I know that sounds morbid but they do!)
My dreams were focussed around abuse, hate, gore and disturbing images. But they didn't always make sense until I had thought about them.
I don't think you should dissregard what the doctors tell you. What you are experiencing may be parts of your subconscious telling you to look more closely at aspects of your life. Please don't automatically think that you are Clairvoyant because you want to beleive it.
Disturbing dreams are often ways of our mind telling us that something in our life is wrong.
For example...I have lots and lots of dreams of my dad dying, being hurt, disturbing images of him. I love my dad with all my heart but there are a few things I wish were different with our relationship. That's all it means. It does not mean that my dad will die or be hurt or that I want that. It just means there are issues that are unresolved. This could be the case with your dreams..or your dreams could be like the others I have....and might just be the conditions you are sleeping in!
Don't dissregard what your doctors say. If you are sleeping in conditions that your body doesn't agree with when you are asleep then it WILL affect you.
For example. Damp, hot, and clamy sleeping conditions can result in headache, migrane, nosebleeds and puffy, itchy eyes. These are what you are experiencing...and the stress that you are building up about these dreams and symptoms will only make them worse. Stress can cause a LOT of symptoms.
Symptoms of stress include:
Headaches
Nausea
Migrane
Paranoia
Muscle pains and aches
NoseBleeds
Sweating
Extreme bouts of stress include symptoms like:
Schitzophrenic episodes and vomitting
It seems like you are in a circle of unfortunate events. Your sleeping conditions may not be right for you combined with the fact you are having nightmares. the stress put on you about these dreams means they only get worse.
Seems like everything is tied into everything else.
I have not covered everything I wanted to say here however I think it's enough.
Please don't ignore what your doctors and specialists say. They are trained and deal with this everyday. Try what they suggest and give them a chance. You might find they're right.
I wish you the best of luck. Try not to get too distressed over it.