I can identify with this to some degree though have managed to control myself by going before I leave the house and projecting where I can go away from home. This may have to do with early toilet training.
Now it remains as nervousness, anxiety, fear. It is in the mind, not the body. You may want to discuss it with a doctor and maybe there is some mild medication to help your anxiety. You will be much better as you get a handle on the fear and anxiousness. Don't be afraid to get the help you deserve and need. Wishing you the best, keep us posted.