Hi
Another HA sufferer here. Mine also started during the peri journey and was exacerbated by my godmother having a very late diagnosis and dying of cancer, and then my mum dying in 2021 (not of cancer, but something equally uncontrollablethat they couldnt even identify to treat). To the point I have such a phobia of any type of cancer that my body reacts even walking past bus stops with Macmillan ads on. I have tried a number of things over the last couple of years, including cbt (which gave me tools to use when I'm feeling calm enough to use them). I still see a counsellor which helps as she helps draw out what is really worrying me rather than what I have diverted my anxiety to. But the main thing that helped was starting a low dose anti depressant in August last year and hrt in December. The anxiety still gets me but I come down from each incident quicker, at which point I can then use the cbt tools. It would defo be worth asking for a course of cbt if you can, some Trusts let you self refer.
I agree with Dotty re looking at possibility vs probability. Just because you might have something doesn't mean it's likely that you do. You could even do a pie chart amd plot in all the other, more innocent things it could be, applying %s to each. You'll then see how small the % of the sinister thing actually is As my GP says to me often, it's all about context. Taking one or two symptoms in isolation is not enough to give you a diagnosis, that's what GPs go to med school for all the years that they do for, to be able to look at all options, including differential diagnoses and apply context about YOU, not the general population.
I learnt through cbt that HA is pretty much overestimating the probability of something awful being wrong with you, overestimating the severity if did have it, and underestimating your ability to deal with it / fix it / cope with it.
Also to add, for the whole of last year until my surveillance colonoscopy I did the same as you, couldn't make plans as thought I'd either be too anxious to go, or would be undergoing treatment for my as yet undiagnosed illness. One thing I realised is that it helps to put things in with the caveat you can always cancel them. Since covid we've done that with trips anyway. And being clear to friends that I struggle with anxiety re planning ahead so they are aware I may cancel at short notice. It has worked so far.
This is really horrible, I feel for you so much, and I do hope you can try some of the things suggested on this thread
Or at least keep talking about it amd your fears, nothing worse than it whirling around in your head.