Dont worry it not as serious as it sounds its just:
when you are in a public place like community hall, pub/restuaraunts etc
when you go fo a jimmy and you go to the urinal (men) do u feel when someone goes to the urinal next door, you can not wee.
this is called shy bladder syndrome
IT CAN EFFECT WOMEN ASWELL!!
here is a link to explain to you more fully
if you wiish not to discuss the you dont have to!!
http://en.wikipedia.org/wiki/Shy_bladder_syndrome