My guess

She was having a fight over there with some old friend of her. Later, few of there friends came to calm them and it was done for a bit of time. She got the feel of someone following her from back. All of her friends are like leaving and she forces them to stay but they leave, she is now alone. And now when she herself is leaving Her mother messaged her about where is she now and she replies with straight home to make her mother calm. But, one of her friends she fought with is now getting the revenge. Ask her friends who were there with her, did she had any fights? Or was she totally depressed and said something about self harm? Was she under some bad influence which she confessed or was caught? "