OK. So while I totally get this isn't a good situation for a health anxious person to be in (I've been there), this isn't someone saying they are "99.9% sure you have a carcinoid tumor", it's saying it's a very long shot but they want to rule it out just in case.
While I get this is stressful, do you see how it's totally wrong for your anxiety to turn that into being certain the end is nigh?
I do appreciate first-hand how difficult this kind of thing is for people with HA, and I feel for you, hang in there. But try not to let your anxiety spin this into something it's not. At this stage it's dotting Is an crossing Ts on an outside chance, based on what sound like very vague symptoms. It's still vastly more likely to be something else, and with those vague symptoms probably even something and nothing.