@sarah60 - Hi! I am another one who has waded through life with various health problems. I’m not going to talk about your anxiety- you have gotten very good advice. I’ll just focus on your symptoms and test findings.

The bright red blood is very scary. However, it usually means the source of bleeding is very close to anus, like hemorrhoids you have had. An anal fissure is also very common. You have IBS- many have periods of constipation and this causes straining etc causing a crack in the lining of anus.

I think it is very good that nothing was found in the intestines on CT.
You already have an appointment at Stanford to evaluate the pancreatic cyst and the liver hemangioma I suppose. If something is precancerous- they will deal with it! Hemangioma are not that uncommon , but they have to nail down more information.

Regarding lower back and groin pain- could be muscular. Have you had bone density testing yet?
Good luck in Stanford! Hope we hear from you after the visit.