I think you have a good understanding of anxiety and know, despite how you may ask for support, that ultimately that's all this is.
You can see how the only difference between the you who actively handled animals & situations that are rabies triggers and the HA you now is the thoughts themselves and nothing external that could be happening to you.
This good because one of the battles of many with HA is just getting to that stage, being past the denial and overwhelming reassurance seeking.
You're absolutely right, the fear cycle is only doing what it has been programmed to do by evolution. It's just in this case it has picked on the wrong target. It would be fine to react with the fear cycle to a rampaging big scary bear. We wouldn't seek to change that response from fight of flight. But in this case a cute, fluffy bunny has become the rampaging bear. The fear cycle doesn't know the difference, it just sees a relevant fear has been built and seeks to reinforce it.
To protect us it's not easy to change that fear cycle and it's fears. We have to work on pulling the rug from under it. Dismissing irrational fears, accepting thoughts are allowed to just be thoughts without meaning. But we forget this is not what that cycle is built to receive therefore our effort it greeted with a
from the subconscious. It wants
as it's conformation it has done something valid (note use of "valid" not "correct"
). And because it doesn't know how to process positive/negative reactions as opposed to negatives, since a big scary bear should remain one, it is fighting us.
Is it so different to how people in dangerous occupations have to learn to control their adrenaline? It's just we have too much of it circulating and all the other mental nastiness it is causing for us.