It'll take her time to return to some feeling of normality, but one day she will learn to feel a part of the world again without her friend.

Don't rush her, let her cry if she needs to cry and above all let her talk about her friend as much as she needs to. Don't tell her it'll only take time - it will take time, but perhaps that isn't the most helpful thing to hear. Be there for her when she needs you, and support her. She's going through a traumatic time, and more than anything she needs support.

The idea of giving her views from psychology may not help... sometimes someone being there is more helpful than advice.

Hope this helps... please feel free to reply. =)

-------
We beat on, boats against the current, borne back ceaselessly into the past.

Losing a best friend is one of the worst things that anyone can go through, it really is, especially at a young age. Especially as it was only around a week ago, she'll still be feeling the pain from it and she will be for quite a while.

Feeling lost will be a perfectly natural emotion after losing someone close, a lot of the time after death people feel as though they have a hole in their heart that this particular person filled but because they aren't there any more part of her is missing.

This will be a confusing time for her and because this is so confusing she won't know for sure what she is actually feeling until she clears her head and has time away from her feelings to think about the situation she's in right now.

Depending on her age, it's possible she never found herself but thought nothing of it until now, this may have made her think A LOT about things in her life.

I'm sorry to hear about what's going on right now, I hope she feels better soon.