A woman comes to you because she hasn't been able to find a job ever since she escaped an abusive relationship. She feels her heart race and has trouble breathing every time she meets someone named "John," the name of her ex-boyfriend. She dreams about that relationship and has disturbing memories and thoughts constantly. And yet, she does not want to talk about the relationship or what happened. She gets pretty upset when you try to tease out the details. Finally, she admits avoiding restaurants and bars they frequented together. In fact, she doesn't go out at all; she says the things she used to enjoy in the past simply don't make her happy anymore. She feels distant and cut off from people, feels emotionally numb, has trouble falling asleep, and feels easily startled.
Challenge: What's the most likely diagnosis?