Just a quick note: talk with your daughter about not "uninviting" her "besties" to her party just because she is mad. I know that young girls will often get mad and then say "You're not invited to my party."
I also disagree about not getting involved with your daughter's social situations. I have always guided my daughter through her social situations, she comes to me and we work on what to do together. I hope that she sees me as a resource and that she continues to come to me as she grows older. I never just listen, I always help her figure out what to do. She wouldn't come to me if she had all the answers. She usually comes up with solutions, but we work out how to implement them together. This has handled bullying and friend drama.
Social situations are hard enough when you're a child. I can't imagine just making your child go through them alone. My daughter has blossomed socially, and she now has social SKILLS. Skills are learned and practiced, and you can't learn without a teacher.