I've tried everything - help!!!

My daughter is a 14 year old who on the surface is a "perfect" little girl.  She is tall, beautiful, blonde and a cheerleader.  She is very popular in school, but has had problems in school since a very young age with teachers and adminstrators alike.  Until recently, I have not had a real problem with her at home and there was always respect towards me and my feelings until, as I said, recently.
I am a single mother and her father abandoned us when she was a very small child.  Before he left, he was gone anyway (mentally) as he was a drug addict and extremely abusive husband.  I couldn't take it anymore and threw him out - - she has not heard from him since.
I know she is bettter off without that kind of influence, but I feel she thinks of herself as a "throw away child" and is rebelling against everything.
This week has been the worst (recently) and I just don't know what more to do.  She has problems in school academically-- receiving D's and F's (something which has never happened). She has never been an "A" student, but has always tried which is all I have ever required.   She is "antagonistic" in classes (according to the parent/teacher forms received) and is disruptive in any way she can find - talking, outbursts, laughing, etc.  In this week alone, I picked her up at a friends house, after only two hours, and she was so high or drunk, she wasn't even coherent!!!  I still don't know what she took as she claims she only had "a couple of shots."  She is still so adamant about her innocence  that my main fear here is some type of date-rape drug - - which is scary in itself.  I have caught her smoking pot.  She lies about everything to me.  She has been suspended for telling a teacher to "shut up! And another suspension for being late to class twice (15 minutes each).   ALL THIS IN ONE WEEK!!!!  I just don't know what to do anymore.  It is so bad that I also found out this Saturday (this week again!!!) that during school vacation her and her friends took my second car for a drive while I was at work!!!!  THESE ARE 14 YEAR OLDS!!!  I found out when a neighbor asked if she got her permit not knowing how old she was!  The scary thing is that I think I'm numb.  I didn't know how to react, how to punish, what to do.  I just don't know anymore.
I've tried counseling over the years, both through school and privately, I've tried grounding, and extreme strictness.....I've tried being understanding and telling her things like, "well, thanks for being honest and telling me , but it is still inappropriate for someone your age"....things like that without punishment.  I've tried indifference and rage....I just don't know what to do anymore!!
This is simply killing me. I constantly cry (which is not my character at all), I am moody and really at my wits end.   Please help me.....someone mentioned Oppositional Defiant Disorder or something like that - - could this be her?  If so, is it treatable?  Please, please help ... I'm really at my wits end.
Thanks.

[Kevin Kennedy, Ph.D.]

Dear Aeslyn,

There's no point in trying to advise you how to handle this situation within the home. You absolutlely need to seek professional assistance; the sooner the better.

Yes, she may be displaying Oppositional Defiant Disorder, but she may be displaying a Mood Disorder and/or Substance Use Disorder. The only way to pinpoint this is to seek professional evaluation. Your daughter may well require brief hospitalization or a short-term alternative-to-hospital diagnostic program. Whatever course the process will take, postponing professional intervention will only exacerbate the problem.