You want my honest advice, as a teacher and a mother (so in other words, I have heard many, many stories and offered lots of advice). This isn't going to work the way it is. Your number one job is to let go of her. Let go of trying to control her, even though you care about her. And let go of her as your roommate. She needs to get control of her life, and this is not how she's going to do it. You cannot obsess over someone who is so wrong for you. You have got to learn to let it go, pal. Sorry. Won't be easy, but it will be worth it.