Oh yes that ever so patronizing "it's all in your head" and you just want to beat the tar out of them, but you feel to crummie to do it. (and it is ever so slightly illegal) What I finally did was say fine get me in treatment, my psych actually really advocated well for me, because I was so sick during the hours that I was in his office. He flat out told them something is really physically wrong with this kid (he is 73, so I will give him that), and he put this in a nice way but the essesence is if you do not keep testing her I am coming after you (he was a big admin at the hospital before his retirement and so he still had some pull).
One of the things that worked for me was getting the pill camera done and an 18 foot endoscopy (not the normal 3 foot EGD), have you had those done?