My 3yr old son doesn’t want to go to school suddenly. He has been enjoying school all this while and one day just came back and refused to attend school. What should I do?

This is very normal as my 6 years old daugther still doing it sometimes (she likes the school). There are some factors e.g. - there are bullies in school - miss daddy and mummy especially if there is a change in the family eg. daddy is travelling for work - overtired due to activities in the previous days - after long holidays