So sorry!
Reese, my kids are small, but my best friend has been through it with her daughter, so I've seen this through with her.
My friend's daughter got pregnant as a teenager, married, divorced, turned into a drug addict (heroin!), hooked up with one loser guy after another, lost custody of her daughter, lost her job, her apartment, her car, and ended up in rehab.
My dear friend tried and tried to save her daughter (propped her up, paid her bills, gave her money) but this lovely girl lied to her mother and pawned her mother's jewelry and camera. Finally she kicked daughter (now 32!) out of the house and into rehab. Told her she can't come back; has to be responsible for her own life and her own decisions. I wish she'd done this years ago.
You can't live your daughter's life. Step back, take a deep breath, and say that you've done all you can do and now she's on her own. It will break your heart to see her make one bad decision after another, but she's going to have to hit bottom (maybe more than once) before she stands a chance of turning her life around.
My friend has accepted that she may outlive her daughter. She also knows that she can't rescue somebody who doesn't want to change. You've probably saved yourself years and years of misery by letting her go now.
Best of luck to you and I hope you are able to live a happier, more peaceful life without all of the drama under your own roof!