It's not in your head!!!!!
I have had OAB all my life; I am 76. I was diagnosed when I was about 16, by a urologist who didn't deal very competently with me - all I can remember is that after I woke up from the anaesthetic and was still non compos mentis, a man came in to my room and said something which I possibly didn't hear properly and certainly didn't understand. My father was a doctor and connected to the hospital, the urologist a friend of his, the result was that my parents, and my older brother and sisters, knew that I had OAB and what it was, I didn't. I had the procedure repeated in later years and got the diagnosis which I understood that time. I was always a bed-wetter for as long as I can remember, needed the loo frequently, and had accidents. If we were out for a Sunday drive, or going anywhere by car, it was understood that if I wanted to go to the loo, the car stopped as soon as possible and I hopped over a gate into a field to go. No question of waiting for the next town ten miles away. Later, if I was with friends (I didn't know many students or young workers who had a car!) I would explain my need to go, and everyone was very understanding.
I have been using protection for years - I survived without when I was young, but looking back, I should have used it. From the 80s on I used protection at night - couldn't find anything to buy except plastic pants at a chemist, so manufactured my own protection with them. There just wasn't any good protection readily available then - something like incontinence was not much considered even by doctors or pharmacists; things were still at quite a primitive stage.
I dated, slept with people.
From the 2000s, protection all the time. I always knew incontinence was not imagined, there was no way that by 'taking thought' I could prevent it from happening. Nor can you. A psychotherapist might help you to understand and accept your condition better - ??
If a woman is worthwhile and if your date/relationship is working out she will not be a bit concerned about OAB or diapers, just sympathetic. If she is not, she isn't worth dating.