Stomach Problems with Anxiety

My Dr. has made all kinds of test due to stomach pains, diarrhea, bloating and anxiety that goes with
it. He explained to me that my food stayes longer in my stomach then it should when it being digested
and that is why I get alot of diarrhea. I have to be very caustious on what I eat. My question is. Is my
anxiety due to the stomach problems that I am having or is it my anxiety that is causing my stomach problems.
when I am having difficulties with my stomach which is pain and then butterfly symptoms then full blown anxiety
ending with negative thoughts and depression. I have fibromalgia can all of this be part of a flare-up or what.
Please help ! I skip meals because of the constent pain I have and its like a roller cycle. Please can you give
me any information on this.
Thank you waiting for your response.