Is it normal to let my friend treat me like this?

Ok, so my best friend, who also happens to be my roommate, is starting to become increasing annoying, and I feel like she's infringing on my personal rights. First off, she's an only child so she automatically feels that she has the right to everything in this world. Me being her roommate, I share the same room with her day in and day out. For some reason, she always feels the need to steal my things or use them, often without asking.Usually it's simply things like a pencil sharpener or my eraser, no biggy. Recently though her laptop charger stopped working so she asked to use mine....and has been using it for the past MONTH. It was fine at first, but then when I was working on a project on my computer, she would whine about her computer dying, and steal my computer cord from my computer. From then on, I kept telling her she needs to get her own cord, and when I refuse to give her the cord, she either gets extremely mad, or she uses some past thing I used of hers as collateral so she makes me feel guilty.
Second, I feel like her slave. It's like she has no legs and whenever she wants something, she asks me to go get it for her. It was fine at first little things here and there, but now she has taken advantage of it, and asks me to get her things all the time. I told her I did not want to be her b**** anymore, and she said she would stop, but she hasn't. It's gotten even worse. Then when I go and ask her a favor, sometimes she gets all pissy or won't do it because she's too tired. She's like a little whiny princess that can't do anything on her own and I'm sick of it.
Third, when she has a guy in her life (which is all the time because she can't live her life without talking to them), she treats me like crap. She talks to this guy all the time through text or what not and completely ignores my texts or answers with maybe a word like "Yes or No" and then not text me anymore. She also tried to blow me off once to hang out with her boyfriend after we made plans. I called her out on it, but she had full intentions of doing it, and acted all sad that I caught her and it made me extremely mad that she had bad intentions. She also blows off her other friends when there is a guy in her life, and it's always "So and So said this, So and So said that" and I don't care!
Is this normal?