I have a question...

I'm sorry but this is a spot for those applying to 大学 to be a doctor, not actual doctors. The 建议 spot may have been a better place to post.
Does she eat alot? Does she skip alot of meals? Are 你 sure she hasn't been ill recently? If 你 realise that she hasn't been eating alot, and she is skipping meals, then i suggest that 你 should tell your parents. Anorexia is a serious illness and if she does have it she needs help, before something bad happens. I hope this helps, and i hope if she is anorexic that she gets better :) heres a website that may help link