Reply to Nightmare Dream Interpretation- HELP!

Hey guys. I need some help determining whether or not this dream meant something...

I had a dream (or a evening mare, perhaps) last evening of looking out the window of my house and seeing a tall black robed figure. I don't usually remember dreams this vividly, but here's what happened: The black robed figure that was outside had vanished. I asked my sister if she saw it. Next thing we knew, the figure was inside the house near the front door. My sister and I ran to the kitchen and grabbed knives. By now, the black robed figure was near the kitchen and within range of attack. My sister didn't do anything, but I threw the knife I had. It hit the figure, but it wasn't affected by it and instead just got really pissed off. As the black robed figure chased me, I fell on the ground and struggled to get up and get away. My sister was running away from the kitchen and away from me, as if she abandoned me. At this point, I realized I was dreaming and woke up...

WHAT THE HELL DOES ALL THIS MEAN?!