A Dream I Have Had

There was a mission bell; I didn't know neither where I was nor that I was dreaming due to the darkness.  I gradually saw the light appearing, and I was at my junior high school with nobody there.  "What's going on?"  I wondered.  It was already over nine o'clock in the morning but there was no one here.  I felt a little bit startled for the creepy situation.  Fortunately, I saw my best friend coming to me with her hands shaking and greeting me.  Then, a shadow rapidly passed through like the wind, and we perceived somebody peeping at us.  All of a sudden, a bloody beast appeared with its stale smell disgusting me, and a shimmering light could be found on its forehead.  At the very moment, the frightening monster rushed to my friend and tore her into pieces; I was very dreaded at the scarlet scene.  Yet, I told to myself that I had to live; afterward, I accidently became an exorcist and defeated it.  After the tough fight, I won, but I looked at my best friend's cell phone which was lying on the ground in desperation.  Unconsciously, my head grew heavy and my sight grew dimmer, before long, I woke up finding myself lying in bed with my body covered with beads of sweat.  I knew I had just a nightmare dream, but I seemed to sniff a slight smell of blood.