hydronephrosis?

I'm 25 weeks pregnant and I woke up in the middle of the night with terrible right abdominal cramping. Half asleep I figured I needed to pee. When I sat down I couldn't pee (usually the opposite problem!) and when I did, the pain was 10x worse and seared through my right side. I almost woke my husband but when I got back to bed it slowly went away after a couple of hours. Im an ED RN and when I went into work, I had an Ultrasound friend check everything for me the next morning. She said all looked great with baby but I had quite moderate hydronephrosis. I called my doctor who ordered a urine test that I'll do tomorrow but didn't seem super concerned. I didn't feel feverish today or anymore pain...just slightly aches. Just wondering if anyone had similar experiences?