Hi and welcome to HCM. I dont think this is an emergency if it last so long. It sounds to me like stomach or gallbladder
tissue. YOu should do abdominal ultrasound
to check this out especaily if pain is aggravated after meal. Blood in stool
in your age usually is caused by some benign disorders such as hemorrhoids, fisuraes,polyps and andgiosysplasie. Cancer is the last thing to think of.
As I said it really looks like gastritis/GERD or billiary colics and you should investigate these 2 first.
Wish you good health.