Me and my mum had the same recurring nightmares

Me and my mum were talking recently about recurring dreams we had in the past. Turns out we had the same recurring nightmare about three black dogs. In her nightmare they were trying to eat me and my sister, in mine they were trying to eat me.

We both used to have flying dreams but both gradually lost the ability to fly in dreams. Starting from being able to fly across the world to being able to fly for short distances to barely being able to get one foot off the ground no matter how fast we flapped our arms.

In my recurring nightmare it was set in our long back garden with a lawn and a washing line down the centre. My mum's was the same setting. At the bottom of the garden there was a cage of snarling black dogs, turning around, the garden becomes sealed and as I turn back the dogs are escaping from the cage.

This was at a time in my life where I could fly for short distances in dreams, so I fly on top of the washing line pole to escape from the dogs- my mum did the same in her dream. I fly from pole to pole but eventually (and all my nightmares finished the same) I would get tired, fly to the ground and let them eat me. In my mum's dreams (and this is where we would differ) she would kill the dogs to protect us kids.

Anyone have any idea what this could mean? Has anyone else had shared dreams with a parent or sibling?

Not sure if its relevant, the dream starts as a garden party then one of my friends knocks down my dad's shed and uncovers the secret garden behind mine. Not sure how my mum's dreams started but they ended up in the same setting with the garden with the washing line down the centre.