Why am i getting gross and brutual nightmares?

2-3 hours of meditating? wow that's a lot of time!
I remember i used to do 15-20 in one sitting and it felt like eternity for me.
I lately had a lot of nightmares as well , some of them made me so scared i had trouble going to sleep at night.
I had a dream recently that i had killed the mother of a deceased friend of mine , the dream felt so real that it was terrifying.
In the dream i was feeling horrible about what i've done and afraid of being sent to jail for life any minute.
Sometimes dreams have meanings , sometimes they're something you've been thinking about or seeing.
The dream i mentioned above , same as you i have no idea why i saw it.
But i believe nightmares are a result of a restless mind , maybe it's anxiety? stress? try to dig deep and find out the reason.

 

I'm at the opposite when it comes to dreaming, I basically don't remember any dreams and yet I wake up often during the night. I don't meditate in the sense of the lotus position, I just sit on the couch for 2-3 hours every day. I won't say I'd love to get nightmares, but also not having recollections of any dream whatsoever is... rather scary.

This is in stark contrast with my childhood years, when most of my dreams were about me jumping out from a window.