This is COMPLETELY normal!
He realizes this is an everyday thing.. He will get into the groove.
This is a big change and kids are not always great with a change in their schedules and their environment, but he is going to eventually just go each day and be so happy, you may feel a little jealous..
In the morning remind him of all of the fun things he and his friends in class will get to do. When you drop him off, stay strong, happy and remind him to have fun and you will see him later.. Then walk away and let the teacher take care of it.. He can sense your nervousness and anxieties, so try to just stay positive..
I know many parents are shocked when their kindergartner walks into the classrooms with no tears on the first day of "real school" and especially the kids that forget to hug, kiss and say goodbye to their parents!