I keep havng the same dream. what does it mean?

well ive had two nightmares at differnt times, but ive only had each of them twice. but those two nightmares would come at random times. the first nightmare is a girl, who looks like the girl from the excorsist. im with my friend and there are other kids in the house, the most vivid part that i remember is me an my friend (who i dont know) are running away from her down the stairs with all the kids. the second time i had the dream it changed a little. when we were running me and my friend werent moving fast enough so the girl caught up to us, she started pulling my friends hair, and grinning, then she started pulling mine, while we were still running diwn the stairs.. there were also less kids. The second dream, is yet again another scary girl, i would say that she is similar to the ring or the grudge except she is ghostly white. from the first time i had the dream all i can rem, is that she could create sort of a holligram in front of you, and say whatever she had 2 say, anyway i was with 2 other girls (who i dont know) and the girl appeared and it was just her head but enlarged, i think she said "why are you running sisters?" and the second time i had the dream alot changed: there was a little boy added, and the girl was actuallu human i guess becasue i was laying in bed and my cousins girlfriend was there and she was like i have 2 show u something and she started changing into the girl, and thats pretty much it. in both dreams i can see two comparrisons: 1. a scary *** girl. and 2. i am running , but these dreams are also affecting me cus i get scared and feel like one of them is watching me. i feel lke that right now at this moment. i dont know if this helps but i am 15.