I have a list of weird a mile long...

Hyperbole. Great, isn't it?
I wasn't entirely sure whee to put this, as I can't seem to find a general help forum, but since Compulsive Lying is part of my problem, I thought it would be okay to post here.

Let me start off by telling you a little about me:
I am nineteen years old, graduating from high school on Wednesday, and I live with my father and step mother.
My biological mother is and has been a drug addict since she was younger than me. Marijuana is all that we're aware of, but she showed up to one of my shows looking like a half dead drug addicted hobo, so we suspect she may have been into something new recently. She raised me until I was seventeen, which was when we got kicked out of our home because of her drug problem. She then found someplace she could stay, but I couldn't. So I ended up having to change schools and come live with my dad.
In the last two years, my mother has seen me in person maybe three or four times, and only kept me overnight once. After that, she went four months without talking to me and moved to Texas to live with my older sister without a word. I had to find out from my Aunt, who found out from a client of the in-home care business they both worked for. I was worthless to her. She kept me from my dad until she couldn't claim me on her taxes anymore, and then she didn't give a ###$. She used to get angry out of nowhere and call me a worthless piece of $#%^ with a big ass. My very earliest memory of her was when I was very young, and I asked her what I had been like as a baby. She very grumpily replied that I had 'bitched a lot.'
My talents include acting, singing, sewing and sculpting. I can write and paint when I'm motivated.
However, I am horrible at staying motivated, keeping organized, and dancing. I also can't really draw.

Now, onto my issue...I lie to my parents here a lot. Not fantastic tales of school drama, but more about my grades and the state of my room. This really bothers them, and I don't blame them. But my stepmom is the most upset. She values honesty over everything. But he also loves good grades and clean rooms. If anything is out of place, I get some long, agonizing lectures about how I want to live and what a slob I am at nineteen years old.
And lately, I've been in trouble for this more than usual.
Away from home, at school, I'm very social, and happy. In my psychology class, we took the Meyer-Briggs and the A-B assessments and I scored as an ENFP and a Type B personality. This all seems very accurate when I'm away from home. But when I get here, I start feeling like I'm going to puke. I get nervous, and all I want to do is hide in my room until the next school day.
But I don't understand why I feel the need to keep doing the things I get in trouble for. I keep my room messy, even if I prefer it clean, and know I'll get yelled at besides. I keep lying to them about grades even though I know it would be easier to tell the truth. I sit and yank strands of my hair out while in class. I cry when I get angry, someone is angry at me, or people are angry around me. Hell, even FEELING like someone is angry at me gets me going.
I love my life when I'm out, but I hate myself when I get home, and every time she gets on me about something.
I have a family that cares about me now. That cares where I am, how I'm doing in school, and how I'll end up as an adult. But I keep ######6 things up.
What can I do to help myself?
I know stopping the lies will be a big help, but I don't know how.
Please help me.