I want to sue Two ppl for defamation of Character

I was accused by someone who said that I was going to burn down their house and kill them. There is also an other woman involved who TOLD her to say that. They informed security for the HA where we live and that security person told the landlord for the home we rent. I got two phone calls on it. Even those two don't believe it happened...the who park is against me and I am being treated as an outcast. I get called names and my husband got attacked by the second woman. At first they said there was proof by a text message. When they realized their phone severs can be subpoenaed they changed their stories. Now say that the security guy lied. I can't sleep...I was called a drug addict...and repeatedly they tell me go take a pill and get away from them...I'm very stressed and now I'm worried that if, god forbid, something does happen to this woman, who will they come after. I;m worried that someone is going to come after me..Since one already went after my husband verbally! HELP