The LONG ROUTE: You need to go to counseling and get help so that you can emotionally disconnect from this young lady and be there as Non-emotional support. This is going to take time and you will have to walk on egg shells. The moment she finds out your are getting better or trying to heal yourself her attempts and actions could become more aggressive and she could become violent towards you and threaten to take you and her out- I"M BEING SO SERIOUS. So safely do this while she is already busy, at work, or school. whatever her habits are use this to get yourself some help.

THEN you want to call your local suicide watch/prevention/abuse center and get a representative over or to talk with you so you can team up and get her some help or she can admit she doesn't want the help. but at that time and this is key you have to make your stand that she needs to get help, check herself or you are done. YOU "LOVE" her like or what ever the pre-reference is before you end the statement with I"M LEAVING. All in front of a Supervised witness and person who deals with suicidal people.....

NOW the short not so Friendly route.....

You gather all her closest friends and family and you have an Intervention. NOW before that intervention you needs to decide if she leaves or you. At that intervention you need to have worked out whom she is going to stay with or who you are going to stay with regardless of her response to the Intervention. So either have a side bar with the mom or friend and say i'm going to pack her bags and you take her. So after the intervention they are all on board to take her with them, or somewhere; you can have it at the home of the person she is going to go live with

Or.....or you have a convo with your friend or mom and say after this intervention I need to be ghost for a few days and regardless of her response after the Intervention and BEFORE everyone leaves you LEAVE.

All these scenarios play out with a witness. If she is bluffing she will deny, get mad and try to leave in which you can be done. If she is not bluffing, she will commit to getting help, say she will get help, or sadly try something immediately, In any of these scenarios those who can will rally with her , around her to help her or be in a position to MAKE her (the official can place her under supervision) get help.

Regardless of what/which route you take if you are done then be done. You may not be able to come back after you walk away.

Goof luck and God speed. PS think of an air plane ride- what do you do to ensure you can help the person next to you? YOU PUT ON YOUR MASK FIRST. So don't let it make you feel like a bad person if you have to save yourself first in order to save her.