Why do girls do this?

Well at first it sounded like she really liked you. From hearing about her I don't really like her. Im a girl and if I like a guy I get jealous if I know he's with other girls hanging out, and I will text them, and want to hang out... But if I see them I talk to them and be around them as much as possible. I would never text other people and ask what he's doing (that's just weird). Honestly in not sure what her problem is. I hope it works out for you but if I was you I think I would just forget about her and find someone else who really cares about you.