So I have worked at my job for about 2 months on this research project. My boss flat out told me that Im basically his "right-hand man" and he trusts me to handle things while he is gone and gives me that extra responsibility. Im fine with that because, frankly, Im an alpha female anyways.

Well all of a sudden, out of nowhere, one of my coworkers has been arguing and butting heads with me consistently. She hasnt done this for the last 7 weeks but now she questions everything I do.

Our boss was gone from last thursday until today and she just wouldnt listen to me on anything. It wouldn't bother me if her suggestions or statements were true but the things she says are wrong anyways. She'll cut me off to teach a new guy something and then tell him the wrong information and I have to correct her. Then, she'll suggest doing something that is completely out of the way and would be easier later on in the day. And when I say that she just questions me. Nobody backs her up or does this to me.

I really can't figure out what her problem is. If she is jealous, she never showed it until now. Just makes my job a lot harder when she flat out wont do what I ask her to. And I have asked other workers if they feel that Im being treated favorably or if they have a problem with whats going on and nobody has said anything about it.

Do you think she is just acting out temporarily? I have to spend another 7 weeks with her and really don't want the next 2 months to be as difficult as they have been this past week. Any advice on dealing with her?