Should I stay friends with her?

Guest

I have a really good friend. We started hanging out in summer of '06, and we've been really close ever since. But we keep on having these fights. She complains that I and trying to "copy" her, when all I am doing is saying that I also like the same stuff she does. And she alos says that I am too judgemental about things. She's not the richest person in the world, if you know what I mean. Her father left her mother when he found out she was pregnant, and she's been father-less. Her house is probably 1000 square feet, and she doesn't have many clothes. So we were in a fight, and I told her that she just goes to the mall to make trouble when she could be working or cleaning. We keep on fighting back and forth every couple of weeks or so, and it's been happening more often, but we've been getting better at it. And the worst thing is, she always acts mean to me during school. She'll ignore me, talk behind my back, and just be plain out rude to me. It's only when we're out of school and hanging out or talking over AIM or the phone, that she is nice to me. She calls me her Best Friend For Life, but she's not acting like a friend at all. And she's really my only friend. Every night she makes me cry because she is always so harsh to me. My parents are really worried about me, and I don't know what to do.
Should I stay friends with her? I don't want to be lonely all the time and friendless.
PLEASE HELP ME!!!