You may be developing cauda equina syndrome where the nerves to the bowel and bladder are affected. You need to let your doctor know ASAP. This can become permanent and it can change from urgency to not being able to go at all. If that does happen...you can't go, go to your Emergency Room...yes, it can get that serious. Life with a catheter brings all sorts of health problems and something you can avoid with surgery to get rid of the stenosis.
Call you doc or spine doc ASAP. Please.
Been there.........Jenny