Hi Kath,
I echo other posters suggestion to see a dr if you are worried. I have GI problems as well and have had black, tarry stools on more than one occasion. That scared the heck out of me, Dr. Google made it 1000x worse! I had a whole bunch of medical tests done and have been cleared. My anxiety would still be through the roof if I hadn’t gone to the dr and completed all the testing.