Frustrated with this girl, what can I do?

Well she sounds like a flirt, and someone who is trying to make you jealous. Obviously, she's just not good enough for you, there are plenty of "fish out there in the sea", I guess she just wasn't the right one. But trust me, everything will get better in time. She's just one girl, there are plenty more out there. Dont let this one bring you down. Keep looking, and maybe you will find the right one.