Problem 7 yr old daughter

Hi ims i'm not sure if im venting or looking for help i just know right now i feel like i want to lock myself in my room away from my 7 yr old daughter.
I have 3 kids 15yrs 7 yrs and 3 yrs.My problem is my 7 yr old I can't handle her.She does not listen, talks back picks fights with her younger brother and older sister and when she doesnt get her way she will scream not just any scream but one that would make your neighbors think your torturing her which im not i swear.She encourages her 3 yr old brother to do things he shouldnt she runs off on her older sister when shes walking her home from school she refuses to do even tbe sumplrst chores oh the lust goes on .It all began when i was about 6 months pregnant with her brother she was an angel up until then i dont know if it was jealousy which i was quite aware could happen or something else but she just changed.Over the past years ive tried many different approaches and she would have her good and bad stages.Ive spoken with the school to see if she behaves the same way but they have told me she is great.So im just starting to think she hates me.I spend many an afternoon locked in my bedroom in tears cause of the way she treats me hubby tries to talk to her but she is starting to show the same behaviour towards him as well.I just don't know what to do her 15 yr old sister tries to help me out buy being my back up as hubby works alot of hours but the 2 girls just end up in world war 3.I dread 3pm when i have to pick her up from school do you know how horrible it feels to say that.I love my girl and she does have her moments where she can be sweet and loving and actually listen but they are fairly rare and well i feel like im at my wits end.Her behavior is driving me crazy does anyone know how this feels please tell me im not alone