I had a freaky dream, what do you think it means?

[Alison]

I was walking down a hallway, turning every now and then, and I came upon a cage. It was sitting on an island in the middle of a lake, and a little girl sat inside it. She looked at me, her face my own, and then she smiled, her teeth sharp and pointed. Blood began to spill from her eyes, which were completely blank. The she began to mutter to herself, then scream. But I couldn't understand her, couldn't hear her. The she began to laugh silently, blood still going down her cheeks, she started to rot away before me. I closed my eyes, then suddenly, I wasn't in the place, with the rotting girl who had my face. I was standing in a stairwell, and a little girl was running towards me, her head down. She ran straight past me, up the stairs. I started to follow her, we ran up these winding stair cases, around and around. As we ran, I noticed she was getting taller, older. We burst through a door onto the roof. The girl ran towards the edge, as she reached it, I finally got close enough to catch her, grabbing her arm. She turned to stare at me with the same face as the girl in the cage. My face. I stopped moving. I couldn't say anything. Couldn't move my body, like I'd frozen. She smiled again, all her sharp teeth flashing. Then she pulled me over the edge of the roof. As we fell, she disappeared, then I woke up. What does this mean?