I nearly drowned when I was pushed into a pool as a kid and I have still never learned to swim. I was in my late 30's before I could stand fully under the shower such that water was running over my face as well as the rest of my head--prior to then, never at the same time if I could avoid it--without reliving the feeling I was drowning. I'm now at the point I can dunk my head under water for a second or two but it takes some working up to lol.
This seems a good time to make the distinction between the cause of the recurring fear, which may not be irrational at all--e.g. anyone would be freaked out for a while after a near death experience of any kind--and the fear itself, which is by definition entirely irrational and caused by past events, not the trigger inducing the fear in the moment.
