J.M.
My daughter did the same thing when she was 5. She would tell me that she couldn't make it in time, but there is a bathroom right beside her bedroom, and another one right beside her toy room. She was just too busy playing and didn't want to take time out to go to the bathroom. I told her that if she didn't make time to go to the bathroom that she wouldn't be allowed to play with her toys. It took a few warnings, but then there were no more problems. It seemed like if there were consequences for her actions, then she was more willing to listen. Best of luck - J.