Crying at preschool drop off

Hi mummies, my child (20 months) has started her Playground for a week and is still crying terribly at the preschool dropoff. This morning, she struggled to wear her uniform and to leave home. It really breaks my heart#1stimemom I need some advice how to help her with the separation anxiety (and how long does your kids take to stop crying when going to school?#advicepls