Two days without peeing starts to be risky for your kidneys. It sounds like you’ve got something pretty serious going on, and you need medical attention. I don’t know if you’re better off calling your doctor or heading into an Emergency Department - it kind of depends on your doctor. Although EDs tend to know nothing about J-pouches, they’re likely to understand your ileostomy. They can easily place a catheter to distinguish between urinary retention (the pee getting stuck) vs. not producing enough. I hope you feel better soon!