Ghost or technical problem

Today was a normal day. We went to school and did work which was handed out. At recess I rushed to eat my food and then went to go and play.Then after that we went back to class and did corrections for mock papers. Then I went to the toilet and the tap was running on its own.I usually saw it often but it kept running and running and running on and on.I was spooked out of my wits.But when I entered,the sensor detected me and the lights went on.As soon as the lights went on, the tap switched off.Maybe it was just my imagination.