That sounds like a very stressful and tough situation to cope with, especially not understanding why she is acting so differently compared to before.
Would she be open to talking to someone? A good place to start is to get some help to figure out what is going on for her. Perhaps a first step could be to visit your GP or encourage her to start seeing the school counsellor.
Another good option is Kids Helpline (1800 55 1800), if she is open to speaking to someone she could speak or chat online to a counsellor.
If she is unwilling to engage in these options, its important that you as her parents are getting support during this time. A good place to start could be Parentline, find out more about what Parentline can offer as well as how to contact them here.
I hope some of these options are helpful to you.
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