I have a question...

I'm sorry but this is a spot for those applying to unibersidad to be a doctor, not actual doctors. The payo spot may have been a better place to post.
Does she eat alot? Does she skip alot of meals? Are you sure she hasn't been ill recently? If you realise that she hasn't been eating alot, and she is skipping meals, then i suggest that you 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