Kids crying at drop off

My 2yo has been attending sch for 4 months. He has been cryingat drop off. Initially he was slightly better after 2 weeks and there were days he didnt cry. However things too a turn after 2 months when he fall sick and miss school plus there was a change in family dynamic . Ever since he has been crying at drop off and im at my wit end. Any parents has kids that cried for many days at drop off. How long in the end did your child take to know that sch is fun and no longer cry daily at drop off.