I have the same bowel urgency as many others on here and can never work out the chicken and egg dilemma: is it psychological or physiological. If I'm very near a loo, with no obstruction (I.e. I wouldn't have to queue, easy access), I'm fine, don't need it. The slightest challenge and all he'll breaks loose.
It affects the jobs I've taken and activities I will/won't do. Travel by car is relatively sorted as I have a camping loo with me always, seats that fold down and tinted windows. If I didn't, I'd be housebound, and it's only this solution that's helped me through the lockdown loo shortage.
Immodium isn't much used to me now as I've taken so much of it over the years. It at least stops diarrhoea by hardening stools but it doesn't stop the urge. OCD has made the issue worse as I often visit the loo anywhere and everywhere just to check that I don't need to go.
During truly anxiety inducing occasions I have worn adult nappies; they offer a little peace of mind but they're also the last taboo, so I still stress over soiling myself. I sometimes think that one day I should allow it to happen, so that the fear of it happening goes away. Because, just like that therapist said earlier, it's embarrassing but I wouldn't die. If it took away the exhausting nervous energy that fills many of my waking hours, it would probably be worth it.
My family is used to me, though it affects them too when I won't do something/go somewhere because there won't be a loo (like a nice walk) or when they're left in a shop queue to pay for shopping because I've buggered off to go to the loo. Once I know I need to go (because I literally get seconds before I do 'go') Usain Bolt has nothing on me. It ought to be an Olympic sport.
I truly hope you find what works for you, OP, as it's a miserable existence. 