You are probably going to get a lot of advise about disciplining techniques so I am going to take a different approach. She's a middle kid and, from my experience, middle kids tend to always feel like they are never getting their fair due like the oldest gets or the baby of the family gets. What I would suggest, if at all possible, is signing the both of you up for some mom-daugther yoga classes. Not only is it a good physical outlet for pent up emotions but it teaches breathing techniques that will help her learn how to self-regulate her emotions at other times throughout the day and it will give her the special attention one-on-one attention that she may really be needing from you at this time in her life.
Of course, I do believe rules, discipline and accountability are very important to all children's development into adulthood but I trust that you will get some really great responses from some of the other moms out there so I will leave this issue to them. I just wanted to throw this particular suggestion out there for you to consider just in case it may be of some help.
Wishing you and your daughter an abundance of peace, love and happiness.