While I can't relate, I do agree with LookingforCalm. Apply to a new job every chance you get.

In the meantime, is your boss the type that is impossible to talk to? If not, try telling her how it makes you feel that she uses you that way. There must be a reason she chooses you and not someone else. Maybe she confides in you more than others? I don't think it's right for her to ride you the way she does, but something must be going on. If she isn't the type you can talk with easily, I would try seeking out her superior and letting them know what she's been up to.

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