If she calls again answer it but make it brief, say you have to leave and you would return her call, but don't return the call. Let her wonder what is going on.

Your best bet might be to just forget about her, I have used the phrase "I can't play monkey in the middle with you anymore" in situations I have been in that are very similar to yours. It is usually a jaw dropper. If you can't keep the fish biting try a different bait.

I truly doubt she is trying to hurt you, but it sounds as if she is taking you for granted. As for her questioning you about other girls? That sounds like an "attention whore" to me, excuse my french. When shes not getting your complete attention she is not happy. Do you want her to be happy or do you want to be happy? Realize that you can't make everyone happy, so you don't have to obligate yourself to her. It is your choice.

Put your self first....not in a selfish way but in a meaningful way.

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Impossible is a word only to be found in the dictionary of fools.

Napoleon I