I need some advice

Hello, my name is Allison. I have come to the conclusion that I am a compulsive liar, and it kills me because now I have almost destroyed my relationship with my mother.
My lying has been going on since 5th grade. Before I was born, my mother and my father weren't having such a great relationship. By the time I got to 3rd grade, they started fighting around my sister and I, and sometimes, they would get very verbally nasty and could last up to a couple of days on end. This really made me feel estranged from the both of them; I loved them and looked up to them, and every time they fought it would frustrate me to no end. But I knew there was nothing I could do about them. I met a girl in 5th grade who, at the time, was going through a pretty rough patch with her family as well. She and I started becoming best friends, and eventually, she introduced me to these people that she was talking to online. I ended up "falling in love" with one of these people, but my parents never knew about it until they found some notes that I had passed to my friend. My mother was upset and told me that I couldn't talk to these people anymore and that she didn't like that I was hanging out with this girl. But even after I was punished from seeing these online people, I still continued to do so. My friend even sent messages from me to them, back and forth. My mom caught me at least two other times, and the last time was the final straw. I finally realized my mistake and decided to end the relationship I had with my best friend. Of course, I realize now why I did all of that - I felt like I wasn't getting enough love from my parents, so I tried to find it in other and risky places. I found other friends, and I stopped lying to my mother, until after my parents split up. I was halfway through 9th grade, and my father left us behind. My mother had been diagnosed with several diseases two years prior to him leaving, like arthritis and fibromyalgia, and on top of that, my parents had been having a bit of financial difficulty. Everything started to fall apart, slowly but surely. There were times where I had done some bad things (like accidentally breaking some household items), but I fessed up to my mother and didn't lie about them. Though, I started lying again once I met another girl in 10th grade, who became my best friend and eventually, my love interest (though we are no longer together as of June of this year). When we first started out as friends, I was still doing good. There was one weekend, however, where she and I started talking, and it turned into us doing online roleplaying. I didn't tell my mother that I had started doing this; of course, she found out. When she did, she tried to understand what it was I was doing by talking to me about it, and she even researched it online. She didn't exactly like what I was doing and she didn't exactly like this girl, but she let me continue on anyways. After I started going out with this girl, I would do things like talk to her on the weekdays without my mother's knowledge, when it was a household rule that we couldn't. I even recieved a few hickies from her, and tried to hide them from my mother. It got so bad that on our first prom night, we told a big lie just to get my ex to spend the night at my house. My ex's mother had a rule that we couldn't have a sleepover unless one of our friends was sleeping over as well, and her mother had to know this person as well. So we lied and said that one of our friends was spending the night, when she wasn't, and we were caught. My mother forbid me from seeing my ex until I could rebuild trust. At the time, all I thought was "how could she punish me"; I even snuck online just to talk to my ex when I could. I realized that was going nowhere, so I stopped, and at the end of the summer I could see her again. I stayed true to keeping trust between my mother and I, until the beginning of this year. My ex suddenly started to withdraw from me, and there were times where she could act very rash and did things to hurt my trust in her. Like, she would tell me she would visit with me on a certain day, and she wouldn't even show up, and when I expressed how it upset me, she'd get angry with me. This kept going on and on, until it got to the point of emotional abuse. I didn't tell my mother about what was happening, because I was afraid that that would mean the end of my relationship with my ex, who I was still holding onto. I also didn't tell my mother that the motivating reason for my top choice of college was so I could be closer to my ex; I was afraid that would make me seem selfish. And now, I'm still having a hard time telling the truth to my mother because I am afraid that what I feel or what I do is wrong. My sister was placed in a mental hospital over the summer due to her own issues of feeling abandoned by out father and by this girl that she became romantically involved with. She began to lash out at my mother and I, even getting to the point where she physically hurt our mother and threatened our lives. Part of her issues included feeling afraid that I would abandon the family after I went to college, just like our father had abandoned us. As a condition of her being let out of the hospital, I agreed to keeping in contact with my sister frequently so she could feel safe about me. The problem was, I didn't voice my own feelings about how I felt wary about my sister because I felt our relationship had become strained; I didn't want to talk to her since she threatened my life. So once I headed off to college, I didn't keep my promise and had pretty much lied about keeping in contact. After several arguments with my mother and being told that if I wasn't gonna keep my promise that I couldn't be part of the family, my mother finally understood how I felt because even after I started talking to my sister again, my sister continued to be nasty and abusive to our mother. For a couple of weeks, things seemed really good between my mother and I, and we both felt like we had a more open, adult relationship. But after she asked me about my grades so far, I hesitated in telling her that I had a 55 in my Ethics class and when I told her that I would ask for extra credit and get exact grades from all my classes, I hadn't yet. Now, she says she doesn't think a relationship even exists between us and she doesn't think she wants to talk to me or even have me home for Thanksgiving. I don't blame her, because I always manage to mess things up because I lie. She thinks that I am intentionally hurting her or thinks that I don't care about her. I don't try to hurt her intentionally; I lie out of fear, thinking that what I did or said was wrong or that my own feelings are wrong. So that I can avoid the shame of telling my mother that I have a failing grade in my class. I'm always afraid that I'll upset or anger her if I tell her the truth, even though she always tells us that honesty is the best policy and that she values the truth over a lie anytime. She tells me that she'd be less upset had I told the truth. I believe her, it's just that my own insecurities drive me to lie. The worst part is, after I have lied, I go to other friends and complain about my mother and how I think she's being unfair and I try to get sympathy from other people. I don't want to be a compulsive liar anymore. I want to have a wonderful and honest relationship with my mother. I hate who I am and I just don't want to hurt her anymore. Can anyone give me some advice or input or even just discuss what they think with me?

Hi, bird-eyes! It sounds to me like the problem is that you didn't feel loved when you were growing up and your mother didn't really understand where you were coming from. I'm not sure if you have a problem with compulsive lying, maybe you just want her love and support no matter who you are or what you do, but you fear that you won't get it.
She doesn't necessarily need to know your grades now that you're in college. You're not a bad person or a bad daughter, it's not your fault that she seems to be disappointed in so much of what you do.
How are you doing? Have you tried talking to a counselor about this too? We can definitely talk here and maybe you'll be able to tell your mother how you feel some day.