Warning contains Self harm

During my life my mother contantly complained that I wanted her to die. I'm not even sure why she would say it whenever the house wasn't perfectly clean. One day about a year ago in the middle of talking or rather yelling she pulled a knife out the drawer and threatened to kill herself infront of me. She seemed very serious about it and I kinda don't remember much but she didn't do it. She blamed me for it though. Kept yelling afterwards about how everything is my fault and I really can't see a knife without thinking about it.