Does this constitute slander and defamation of character?

This lady I know is saying things about me because of something small. She is writing me on facebook. She is calling me names, telling me I'm trash, talking about my children and family, I'm a thief. Now she is talking about bringing a suit against me for something idiotic...a vacuum cleaning that I had nothing to do with. She has also talked to my parents and a lady I knew for a long time about all of this. Can I bring a counter suit against her for slander and defamation of character?