Peeing caused by anxiety?

Whenever im in a car ride or anywhere that i dont know where the bathroom is, i get the feeling of peeing. Normally when i am hanging out i can go 6 hours without peeing. Ive been to the doctor and i have no physical problems. Does anyone know any anxiety excercises? Any way to keep me from thinking anout peeing? Even when i just urinated at a gas station for example and i get in the car and i dont know how long ill be in it il have the feeling to pee 5 minutes after peeing. Any advice?