Why did the evil Gina think her boyfriend was different?

I just watched this movie, and I didn't understand why, if she was the evil mirror version of herself, she would tell the psychiatrist that she thought her boyfriend was acting strange and was not his true self. He wasn't the real boyfriend, because he'd killed him, so they were both the evil mirror versions of themselves. In other parts of the movie, the evil versons seemed to know and recognize each other. She seemd not to know she was the evil version of herself, but still, if she wasn't her REAL self, then she wouldn't have known the real boyfriend at all and wouldn't have known if he were acting differently from normal or not. I didn't get this part of the movie, it seemed contradictory to me. I liked the rest of it, and thought it was in interesting idea and take on Invasion of the Body Snatchers. It was scary,though there were ways it could have been improved. Another problem I had with it is the other mirror images seemed to know where they lived, but she didn't recognize her own house.