Hello! I went to the toilet today (twice) and in my urine there was a red piece of tissue (not big enough for a blood clot) both times. Both times I had held my urine for quite long as there was no toilet available and my stomach hurt a bit when I went to pee. However, I just urinated again and found that it was fine. My stomach pain was also gone. Could it be because I held my pee in and irritated my bladder lining?