This will be quick for now, though I have more thoughts.

In my family, gallstones are directly related to not enough stomach acid. You can have no symptoms to a lot of them. My Mom's belching and other symptoms were not alleviated by taking her gall bladder out. Only taking Betaine HCL, 12 years later, made her GI symptoms go away. And she had a low B12 too. Betaine is a very simple solution to no stomach acid as opposed to surgery.

Your low BP could also be a sign of Addisons.