Oh hugs, Mel.
I know the feeling. DS1 was like that with DS2, just so rough all the time and it felt like all I was ever doing was breaking up fights. He would shove other kids for no apparent reason too, but mostly his brother. Do other people look at you like you should be doing something about it? I really hated the looks like I could somehow fix my son who just seemed to want to hurt his little brother at every opportunity, that I was being a terrible parent for letting it happen. I smacked, I gave countless time outs, I spoke to him in a rational manner, as did everyone else I know, but it didn't make a scrap of difference.
It isn't your fault. She will grow out of it and you will start to like her again, but it could be a while. I am not really sure when the violence stopped, but it did, and now they get along really well (most of the time). Good luck trying not to strangle her or give her away.