She was in a very toxic and abusive relationship and it completely ruined her in every way possible. She was psychically abused by her dad at some point while her mom just watched, not being able to do anything.she has ptsd or some sort of other mental disorders due to all these trauma. she blames herself for a lot and carried the feeling of being a burden and guilt with her all the time.

You've known her for a while now, she was clingy and very talkative around you. You were her comfort person. She felt safe around you.