The sad answer to this is that she’s not relationship-minded, she’s too worried about herself to be able to spare any energy to think about her relationship.
There’s a sort of Maslow’s hierarchy to relationships. Each person has a set of really basic needs they need to have met. If they’re not getting those needs met, if they’re in a relationship, then they’re going to blame that other person for not meeting their needs, because that’s what people in relationships do, right?
This is why people say that if you’re single, you should learn how to be happy being single before you get into a relationship. It will keep you from blaming the other for weird, illogical things.
Your job is to find out that deep-seated need that’s keeping her from focusing on creating mutual happiness. I would suggest simply asking her about her day, about her life, about her everything. You won’t immediately get real, actionable information, but just focusing on her will help alleviate her loneliness. Once she’s feeling better you can start to ask her deeper questions.