Is she still my friend?

Sounds like a friend I had a few years ago. She would ditch me for one person 또는 another, even for those she didn't like.

Through knowing her I learned that some people don't have friends, they have people who are of use to them and nothing more.

This may not be the kind of person your friend is, but I do know that 당신 need to have a talk with them, and find out where 당신 stand as your friendship goes. Your either going to have a better relationship having talked about how 당신 feel, 또는 당신 find that your friendship is over.
It sucks if it's the latter but at least 당신 know one way 또는 the other.

I agree with SynsAngel, talk to her and 당신 know where 당신 stand. If she goes off with other people and makes 프렌즈 with them, then she isn't a proper friend. I had a friend like that, she became a good friend but then she talked to me less and made 프렌즈 with someone else, and she did it to other people as well. 프렌즈 are people who acknowledge 당신 and they stay 의해 your side.

No she's not a friend! Just a sucker for lots of acquaintanceships... Not worth it, but if 당신 really want to know if the friendship is true... Test her!

Well if this keeps happing talk to her and tell her how 당신 feel. If she doesn't stop I say it is time to either..
A) Tell your parents about it
B) End the friendship for good