My boyfriend's mother hates me and she's hell-bent on separating us. What do I do?

Even though I did nothing wrong, my boyfriend's mother hates me. She's hell-bent on separating us. She told me to leave her son alone and threatened to call the FBI. Right now, I'm so upset that I'm thisclose to resorting to self-mutilation and even music can't console me. :( What do I do?