Too bad that things like that happen everyday and that is a shame. I will never understand why human nature has such mean streaks, Try and be strong . Do not let the "mean" girl bother you. you still can be friends with ur friend but make new friends.Join a school club or library program etc. You will be able to make new friends. Anthony Courville had good info .We hear you. Please know we all go through this. I did also as a child but I still made new friends and had a wonderful family support system. Hugs :)
There is nothing to say to her it's her choice move on and make a new friend. If she some day asks you what ever happened to your relationship you tell her, "I could not be friends with you because you where friends with someone who was mean to me."