hello my name is dave
it can some times take some time for a young child to get settled in to a new school/preschool some time you might need to take a day of work to stay there with him/her to reassure them that is is a safe place as they don't know any one and it scares them. until that get comfortable in the school/preschool it will always be this way
thanks for taking your time to read this reply
best wishes
dave