Dream of girlfriend

Starts off as memory of ex- girlfriend and I kissing with her on my lap in a park. Background switched to bedroom. Things got more intimate and she pushed me back onto the bed. Suddenly I was restrained, couldn't move or do anything. Ex- girlfriend 's face then changed from loving and passionate to pure hatred, anger and malicious delight. She pulled out two knives. She started torturing me - lots of methods but knives were the main ones. Lasted ages, couldn't wake up. Felt the pain very realistically.