This sounds complicated and like you don't have the greatest of friendsip luck. First of all if one of your friends is doing somthing you don't like and being to mean to you most of the time, don't bother being friends with her. You might want to make a list of the good and the bad of your friend and if the bad outways the good, stop being friends with her. You shouldn't be in a bad relationshp with anyone because you might end up getting hurt and that isn't good.
I would suggest trying to hang out with someother people. Maybe invite some people to go to the pool with you or go see a movie. It might make you nervouse to hang out with new people but just be bold talk to the people at school and then if they seem nice invite them to go somewhere.
As for everyone being turned against you because of your "friend". You should just tell your class that you didn't do what she siad. and then just try to forget about it. It might be hard but if you just ingnore any teasing or whatever that comes from it then it will go away.
Never stay in a bad relationship. It just doesn't work.
Hope I could help,
Amy
I had this friend and her name was Brooklyn. She always acted like the boss over me and every time she left me alone, the next day I would go back to her. Then one day I decided not to go back and the day after she turned every one against me by telling them that I did somthing I didn't do. Now I have another friend that is mean. All of the class likes her. Some of my friends from my old school tell me that they don' t like her but later I see them hanging out with her. Also she trys to get me in trouble Sometimes it even works! My school is far away. I barely get to see my friend but I always see Broklyn. What should I do???