What the hell is going on? pt.1

I work late at the P.D. Small town, 15 officers in all. two weeks ago, I got dispatched to what I thought was just another domestic problem. Dispatch had said that a call came in from 911 about a lady attacking her live in male partner. Sounds routine, I know. I have played this out 100 times you knock on the door, they come to the door, you ask what the problem is, no body talks, and you go on about your day. Most of the time, some young idiot slaps around another young idiot. The person who got hit calls the cops, and 5 minutes later when the cops get there it's all simmered down and after you are gone they role around in the sheets. Nothin like a little bodily fluid exchange to fix just about anything. That phrase would come back to haunt me later, I found. I arrived at the home at 10:30 pm. Exterior lights were on. I walked to the door, and knocked. Thats when it started to get strange. The door was open a crack, which is strange for around here in January, 10 degrees on a good day.I drew my weapon and flashlight and I opened the door slowly , worst mistake of my life. I saw something I will never be able to get out of my head; a woman, or what used to be a woman, eating the face off of, what I can only assume, was once a man. She.....it looked at me with whited over eyes and sceamed a high pitched scream. I told her not to move, she did not listen. She lunged at me with speed I have never seen. She was on me, clawing at me, snapping her teath at me, No humanity in her...it's eyes. I held her back with my hand, damn she was strong. I strugled to get at my gun, which had been knocked from my hand when she lunged at me. My flashlight was on the floor throwing our embattled shadows on the bloody wall to our right. The flash light was closer. I snatched it up a bashed her in the head.....nothing...Again and again I smashed that inhuman face until she finally loosened her grip enough to get my pistol. I fired once, still on the ground. She was thrown against the wall. Shot to the chest, no effect. Again, in the chest, more blood on the wall, no effect. I could not believe it! Even people on drugs knew when to stay down. Finally, I put one between her eyes. Limp. Lifeless. Dead. What the hell was going on? I thought it was over. Wrong answer. The man without a face was standing behind me, and he screamed. God that scream. He dove at me. A shot to the face ended his ambitions of making me a meal. There I stood, covered in blood and sweat. Was any of it mine? Hard to tell. Back up got there just in time to see me vomit. I have never shot a person before. Never thought I would. The next couple of days made intimately familiar with horror, fear, and death. My girls.....oh god my girls.