You sound exactly like me. It all started age 13 and at 18 I was diagnosed with IBS and brushed off.
I got extreme anxiety around the issue. If I was inside I could go all day not needing the loo. But if I had to go out then my stomach started churning and I got cramps and diorreah. Purely brought on by the anxiety.
I was OBSESSIVE around knowing where every loo was. I got a “can’t wait” card which gave me some confidence as I knew I could use it in shops where there weren’t customer loos but I could hopefully use the staff loo.
Breathing exercises. They’ve got me through some tough times. Breath in Through the nose for two and out of the mouth for three. Repeat and repeat and repeat. That has helped me loads of times when I’m sat in a car that has stopped on a motorway or something.
When I have to go, I have to go. I can’t hold it. I did get some adult nappies which I wore extremely rarely, and never actually “used” but they gave me some confidence.
Anyway it turns out I didn’t have IBS. My parents paid for me to have a colonoscopy privately after Getting some blood appearing and the GP fobbing me off and I have ulcerative colitis.
I could have written your post and I sympathise so much :( It sounds like you’re like me and the anxiety is more of a trigger than the actual bowel problems! So treat the anxiety! I take citalopram for anxiety and it changed my life. Ask your GP. It takes a few weeks to start working but it was a life saver.
My biggest tips otherwise are the breathing exercises, and actually being able to come to terms with the fact that if you have an accident the world won’t end. I keep a bin bag and loo roll in the car in case I ever need to quickly jump into the boot or back seat and poo in the bag.
But treat the anxiety. Because without that you’ll be half way to normality.