Obviously, this will not be easy. You're right. If you have surgery, you will wake up with a catheter, but I have an out of control anxiety problem and I didn't find this to be a big problem. If you're talking about having to use one on a regular basis, that doesn't have to happen. It might, but I know several folks who have dealt with prostate cancer and none of them ended up needing a catheter regularly. But to deal with the fear, well, that takes therapy and maybe drugs. But again, what I wouldn't worry about is the one they put in you after surgery, if that's what you're concerned about, because you won't be awake when they do it and you won't really notice it until they take it out, which is pretty quick. Are you facing surgery?
When we have an intense fear or phobia, that's hard to get over. Since it is situational, what about something like a half of a xanax before they insert it? Dentists use laughing gas for a reason! Doctors and nurses don't, but you may need 'something' to get through this.
I'm so sorry this happened to you. It's so understandable that you have fears around this.
Since you can plan ahead of time for scheduled medical procedures, and use medication as part of your strategy, maybe you should also find a strategy for something unplanned, like if you are in a car accident. Maybe you and your psychiatrist can develop a plan with coping strategies in a controlled setting now so you're prepared if that ever happens. Maybe planning for it will give you a sense of control, and if you have one hospital you use regularly, they can add something to your file.
"that I thought I'd dealt with admirably" - you probably have dealt with it admirably. I mean, you're here, reaching out for help, right? That's coping. That's dealing with it. That's strength. Dealing with it doesn't mean you'll never have to feel it again. It means you learn better ways to work through it each time it comes up.
A therapist once told me that this isn't something we ever "get over". We learn how to "get through". You're getting through admirably, for sure.