Harassed and verbally assaulted by school parent

Iv been having a few problems with a mother at the school. Both our children keep falling out as kids do. Last week this woman confronted my child and called her a little bitch (she’s 9). I confronted her and she just gave me lots of attitude! Yesterday afternoon all hell broke loose, she waited for my child to get out of her classroom and decided to chase her verbally abusing her. I was trying to push her away telling her to stay away from my daughter! My daughter had to be taken away by a teacher. We ended up screaming at each other for abit after that. We’ve spoke to the school and things have been put in place so we can avoid each other but she keeps harassing me and shouting at me. She was waiting outside the car park for me but I had left by this point. I’m very worried her and her friends are going to do something to me and my kids outside the school gates, I don’t know what to do! My nerves are shot!!