Where the bedroom Ends

This is also from my writing class this summer. The whole pint of this activity was to see if my teacher could guess what genre I was writing. (Note: This is, again, just a short story)

I walked into my bedroom in my house. This room was all too familiar to me, bur it was that one day when I walked in that room that I noticed something different about my room. I couldn't put my finger on it...until I turned on the light. Everywhere I looked there was blood. To the left of me blood, to the right the same thing, it was then that a scream escaped my mouth. It wasn't the blood that made me scream, no not that, but whom the blood was coming from. My best friend in the whole world, Serena. There she was in the middle of my bedroom floor with a pool of blood around her.
"What happened to you?" I said as the question escaped my mouth in the tiniest voice i had ever heard.
"Is that your friend there?"
I jumped. There shouldn't be anyone else in my house but Serena and I. My heart started pounding.
"Who...who...who's there?" I questioned
There wasn't an answer. I must be losing my mind. I could see why. This couldn't be happening to me, and definitely not to Serena. It was there that I started to bawl. I couldn't stop. The hot tears just came streaming down my face in a never ending flow. I realized that I was on the floor on my knees. I shakily stood up the tears still streaming down my face.
"Is that your friend there?" The same voice that I heard before said again.
This time I knew I wasn't making things up in my head.
"Who...who's there?" I asked with a bit more confidence in my voice this time.
"Answer my question, and I'll answer yours." The voice replied back.
I decided not to listen to him and ask again, "Who's there?"
There was silence, and a long pause. I slowly turned around, my eyes focused to what was right behind me the whole time. A man, a man that was dressed in all black with a black hood over his face. I saw something glisten in the light of the moon. All I had time to do was scream, and everything went black.