My 15 year old daughter...Im out of ideas?

In the beginning of summer vacation, all was well. I had a nice polite 15 year old daughter who got good grades, always did what i asked, and never acted spoiled. Ever. Then she started acting funny towards the middle of summer, and i didn't know what was wrong. I thought my sweet little girl was finally turning into a teenager, so i didn't do much about it.

About a month later, I notices she started being very rude whenever you would ask her anything, and always had an attitude. She also started to collect sunglasses, and would wear them everywhere. She would never take them off. She stopped eating dinner downstairs, and started taking it up to her room. Then she started looking sick, so i told her she needs to go see a doctor. She went INSANE and had a fit. She has never done this to me. Later that night, i went to her room to go see what is going on with her, except she wasn't there. Its 10:00 pm. She was supposed to be in her room. I conducted a search of her room and found too much stuff that i wish i hadn't. That begun our[more like my] battle with every drug you can think of. Pills, heroin, weed, meth, cocaine, acid, pcp, alcohol and more.

That night when she got home, i was waiting for her. She came in reeking of SOMETHING terrible. I dont know what that smell was but i did not like it. She had blood shot eyes, was stumbling around and couldn't form coherant sentances. I heard a car drive off and ask her where she was. She mumbled "out front to get something llaaatterrr*cough*". I told her to stop lying and i found everything in her room and pointed to it on the downstairs table. She attacked me, and ran off. I searched the city and 3 hours later found some people who knew her told me where she might be. I went to where they directed me, and thats where she was. I had to drag her kicking and screaming into my car while she was calling me a child abuser. she bit me, tried to move the steering wheel so we'd crash, and threw her phone at me. She fought me and punched me all the way into my house.

when we got home, i put her in her room and held the door shut from the outside for about an hour until she tried getting out the window. I heard it open, and she was in the process of jumping out of our second story window. I dragged her to the bathroom and shut her in there until she stopped screaming and trying to break the door down. I opened the door and she was quiet and sitting on the floor and asked if she could come out. I said yes and walked her to the living room. Neighbors were at my door asking if everything was alright. Its 4 am now and i told her we had alot of problems and a long road ahead of us. She said she was sorry and wouldnt do it again. I explained to her that addiction doesnt work that way and she is going to counseling and she would no longer have any freedoms or anything of the sort until she earned it back [and here we go, another tantrum]

Anyway, that was about almost 4 months ago. It was 3 weeks before school started. I put her in therapy and she is supervised almost all the time except her "alone time". She has no door and I search her room throughly once a week randomly. She goes to a new school, and Her aunt picks her up and lunch and she eats lunch at my sisters home. I pick her up immediatly after school. She has a cell phone that can only call me, her aunt, her grandmother, and 911. She gets drug tested every week, and spit tested daily.She doesnt get money. If she needs/wants something she has to ask me and i will go get it for her, or go with her to get it. She must maintain a 3.0 GPA [she started fresh this year!] or she loses her 1 hour of alone time twice a week. starting about two months ago, I leave the house for a hour and she gets time alone.

Anyway, today when she came home from school she told me she thinks she is pregnant and she hasnt had a period in a 2 months.

I asked her to explain herself and she started crying and told me during her "alone time" one of her guy friends would come over and they would have sex just to spite me, and then he would leave through the back.... And she never asked him to wear a condom. oh and shes sorry.

I swear this kid is out to ruin her own life. What the hell is going through her teenage skull?!?! I admit the alone time thing was the dumbest mistake i have ever made but Im at my wits end with this kid. The last thing i want is to give up but i just dont know what to do anymore. Her father is not involved in her life except for sending child support. Thats it. I dont even know what to do now. I cannot afford another kid because i had to cut my hours in half so i could baby sit her. If i didnt have to baby sit her, i could afford much more but right now all i can manage is her therapy, $400 a month in drug tests and our other bills! She has a doctor appointment on Monday.Now if shes pregnant i cant leave her alone because obviously she has a problem with doing things that get her into trouble when she is alone