Why Does my 'best friends' disrespect me so much?

Hey. Im Maz, and my best friends Louison. We went to primary school together and yeah, we hated each other until we were in year 6. Then it all changed, she asked me to sit next to her in cl, so I did. I think at first she was trying to have a laugh, because she was the popular one and I was the boffin who always had her head in a book. But then we started going roiund eachothers, haveing sleepovers, we were bet friends. Even though she was popular, she was abit on the chubby side (but still gawjus). But at the end of year 6 everything changed. We were going to different high schools. She was going to the rough school with the rubbish teachers, and I was going to the strict school, with the really good teachers. nobody from my school went to my high school. They all went to Louisons, Not because of Louison, It just happened to be there choice. But my dad was reamining firm, saying I must go to the better school. Im not angry that I went to st nicholas' (my current school). Im happy that I went to a better school. I made friends and Yeah, I wasn't the most popular girl, but Does it matter in life to be popular? But iot was the opposite with Louison. She was queen bee, And you know how big it is to be the most popular girl in year at high school. I know most of her new 'friends' are just using her for popularity, but whenever I try and tell her, she has a go at me. I know im overprotective but I don't want louison to do anything to stupid (trust me, shes the sort of person who would). Her new friends always gossip about me, they call me a dork and ask louison why she was ever friends with me. (My other friend tells me this(and yes, she not stirring, I can trust her)) The worst part is she doesent say to them, Don't be so mean, shes my best mate. She gossips back and says, yeah I know, shes a major dork. Okay, so I love wirting music and reading books, not slagging off every girl in the year, SO WHAT?. Im not as confident as her, but every time I confront her about stuff like this, she has a go at me, and some how, I always end up saying sorry. Recently shes been asking me Are you going to tramps? She always goes to tramps under 18 night and expects me to go with her. I don't want to. I wanna go with somebody who'll look after me, Like my older sister. My mums died, so I often go to her mum with alot of my problkems. But this is something i cant tell her. I mean its like somebody going up to you and saying your daughters a *****. Theres also been alot of talk of what we wanna be when we're older. My pions with singing, but Louison likes doing that too. She loves outshining me. If I start singing she'll overpower me with her shouting voice. its annoying. So I wanna be a singer but then As a joke I suggested glamour modelling for Louison, and she took it seriously, so Now louison looks up to people like katie price. She also Keeps saying to me stuff like, You need to stop listening to your disney **** (demi Lovato, JB, stuff like that) and listen to 'real music' she puts on a dizzee rascal CD. She also told me to stop being such a baby. But the worst thing shes ever done to me, Is say to me, I wouldnt' care if my mum dropped down dead. She probably didnt intentionally mean it, But how the hell can you say that to somebodys face, when You know that there mum has died. I just dont know what to do anymore, I hate her so much, But theres something which is making me wanna be her friend, I dont know whether its the connection Ive got with her family. Her mum and ad are split but when we went to her dads, me and her step mum got talking and she was telling me how louisons other friends are rude and mean and impoliete. You might have guessed by her name that shes full french? Her mum is from france and so's her dad, She speaks absoloutley impecable french, and her stepmum is full german so shes also quite good at german, Yet she doesent want to take them as a GCSE, Louisons a bright girl, But she just pretends shes not because apparently its 'uncool' to be smart. Shes in bottom set for everything. It infuriates me, Whatever I tell her goes in one ear and out the other. I dont care if nobody answers, I just had to write this, let it out and ask one last thing, Has anybody else had/got a riend like this and if so, How did you tell them. Much appreciated. Thank You!