David,
Keep pushing for a clear diagnosis, ruling either in or out. My partner of 24 years was finally diagnosed with Stage IV, non-operable Stomach Cancer. It took us 3 different doctors to finally give us an answer to a 50 pound weight loss that was unexplained. He had NO symptoms and felt great. The third doctor finally said we need an endoscopy, post haste. It even took two of those, as the first one was performed with normal sized cups. The second one, he used the "Dolly Parton" model which could take a bigger chunk of Linitis Plastica lined stomach tissue with which to get a definite diagnosis.
My only point is, that you alone, know how your body is feeling. As long as you haven't crossed the line into hypochondria (fairly easy line to blur, lol), your body will always tell you when something isn't right. Listen to it.
Hang in there and get your diagnosis. Take care of yourself, you don't need to have a breakdown. There's always time for that, later.
Best Wishes, Scott