I understand what you mean, it took my soon 3 month to get accustomed to the school. We tried contacting the daycare etc and ask whats the reason, the teacher said that he has no problem in school, after we leave, he would simply play around and listen to teacher and infact is very playful and kind. The teacher considered him to be one of the well behaved ones and he has a favourite teacher to which he will run to incase of anything or he needs something.
Every morning he would cry not to go to school. Then we consult the teacher, the teacher gave us some helpful info
1. Never trick your child into going to school.
2. Keep reminding him of school and all the fun activities.
3. Show him a picture of him at school and playing and happily having fun.
4. Never bribe the child by saying if you go to school you get this and that.

After we tried that, within a week every morning we would enter school happily and said bye bye to us. He is okay now.