How to prevent shared dreams?

I've been having many shared dreams lately.
a few months ago I had a dream of this weird pedophile made of paperclips and he was feeling me up, so I killed him by ripping all the paperclips off his face. In the dream a few classmates of mine were watching the violent attack. When I woke up I talked to all of them about the dream and the one person who's face was clear in the dream said she had the same dream and provided more details about it. This freaked me out. I grew suspicious of what would happen next. Why is someone I barely know walking my dreams?
My next dream was a few weeks ago. In the dream I took a sniper riffle and shot a little girl outside my house. I was drinking. I went to court and my lawyer was trying to hide all evidence of the fact I was drinking. My sister was there throughout the entire dream seeming to stalk me.
The final dream was a few nights ago. My life was being threatened by this guy with a knife. At first I begged for my life. It felt so real and scary. I got smart though. I waited until the knife was near me and pretended like I was still scared. I put my hand on the knife as if to push it away, but quickly grabbed the blade tight and threw it, and screamed what's the point! Why do you want to hurt me? Then my mom came around, and all of a sudden we were home. The guy was upstairs. He had a gun and a knife this time and was coming down stairs. I grabbed a knife and told him to go back. He didn't so I stabbed him. My mom refused to leave the house with me.
Today she mentioned having a bad dream about me and to be careful. I'm not close with any of the three people that walked my dreams. These dreams hint at my past that I've tried to keep hidden, but now they threaten to reveal themselves. My mom will soon talk to my sister and they will probably talk about the dreams they both had of me. I'm worried someone is going to uncover my past by walking in my dreams all the time. How do I get people out of my head??? This is very important that I stop people from entering my dreams.

Why are you not close with your sister? And not everyone thinks dreams are from your real past because it's just a dream and only you know what it means. If others, like your sister and mother go in your dreams they won't go to you or anyone else and say "hey my sister/daughter had this in her past." It doesn't work that way, because when it is your dream only you know, and when it's others dreams you basically are clueless and don't understand the dream you are in.
And about stalkers based on people you don't know that is harming you all you need to do is fight back, and what you did is right to do. Just don't worry about your mom and sis knowing your dreams because it is actually like any dream and they think it isn't real.
Hope this helps.

I'm not close with my sister simply because she's a lot older. I don't remember anything from when she was living with us, and I hardly see her now.
I know they won't understand, but the thing is if they talk to each other about having these dreams they might think something is up. My family is very intuitive, and always thinks (or sometimes know) that a dream or a suspicious feeling has more meaning that it suggests. So far they've not seen things from my past in my dreams. They've only seen my over active imagination. But I often have dreams about my past, and if they see one of those... I think they'll figure it out. The dreams are so real and filled with very in the moment real emotions.
In my dreams when they seemed to be stalking me they did seem clueless, and it wasn't too real seeming. But my mom warned me to be careful and that she had a bad dream about me. I don't know if she was in my dreams or not, but I hope she never finds out.
Thanks for the comment. As long as I act clueless if they mention the dreams I think I'll be fine. I just don't want them seeing the real dreams.

yr dreams are not just in yr head. check yr premise