Trust me, HGE is so awful....there is no way you would be left to wonder. The bleeding is profuse...not just a little bit of blood in stools.
If you can, I suggest taking her to a board certified internist. Maybe they can get to the bottom of all of this. You can find one at:
www.acvim.org It might cost a bit up front, but would more than likely stop all of these frequent visits! In the end, my guess is that you would spend less money!