What do I do if I think my friend is in a toxic relationship?

*trigger warning. So.... I’m a seventeen year old girl and I’m really worried about a friend of mine (just turned 18). We’re seniors in high school and we’ve been close since we were like 10. She’s always struggled with mental health and and I’ve always tried hard to support her, but recently she’s said a lot of stuff that’s really stung and the more I think about it the more I feel like I’m enabling her self-destructive tendencies. About a year ago she started dating a guy (she met at a support group for high school and college age kids with depression. (He was 22 then, 23 now.) Her parents sent her after she cut herself worse than she meant to and panicked because she was bleeding a lot, called me, and I had to calm her down and tell her mom to take her to the ER. She had stopped cutting for a while but apparently that was a really bad night. When she met this guy she was starting to recover, but was still in a really vulnerable place. He was a junior in college and said he was going to meet school afterwards, but still lived at home with his parents (not standard for students at his college.) She was still seventeen and on top of her mental illness didn’t have a driver’s license, had never had a job, and had failed a bunch of her classes junior year and wasn’t sure she’d be able to graduate in time. I tried to talk her out of it but she was dead set on starting a relationship with him. A couple weeks later she called me all excited saying she’d lost her virginity to him (without protection) then she stopped talking to me and her other friends all together and started skipping classes. Now she’s trying to talk to our friend group again as if nothing ever happened, at first she said if he got her pregnant they’d agreed that they wouldn’t get an abortion because they were both “catholic and therefore pro-life” (she was always a practicing catholic, but always staunchly pro-choice and always said she never ever wanted kids for as long as I can remember) but now she’s actively trying to get pregnant. Any time anyone tries to talk her about her relationship she lashes out at them. Apparently her older sister asked her to at least use protection and she isn’t talking to her any more, and the last time I told her I didn’t think it was a good idea to trust this guy she just told me I was “jealous because I’m just an ugly virgin who thinks I’m better than everyone else.” Now every time I’m around her she says things like that to hurt me. What should I do? I’m trying to block her out, and I just got into my top college out of state, so I figure I can cut her off and once I graduate I’ll probably never have to see her again. I’m just worried that something will happen to her and I’ll blame myself for not doing anything. Does anyone older and a little wiser have some insight?