DD is in Year 1. Apparently in reception, they weren't allowed to go to the loo during PE and so she didn't ask today. As a result, by the time they were getting changed again, she was absolutely desperate and couldn't make it to the loo in time. The other kids saw and are being mean to her, and she is now distraught.
I don't have any experience of how unusual this is at their age. I would hope that they will have forgotten tomorrow and will leave her alone, but there are a few boys in her class who seem to take great delight in finding someone to pick on, and I am worried that this is going to make her their next target.