"Mom, what day is it?" Its Thursday. "Oh....I don't go to school on Thursdays."--the kindergartener says the second week of school.
By now, everyone in our house is in school (even Dad...online psych class!). My kids always need some adjustment time. After doing this for several years, I think I have figured out most of the tricks of the trade on getting them adjusted.
Although they have all asked, I don't grant sick or personal days the first month of school (this year is the exception as my daughter was actually sick one day). They go, everyday, all day as much as possible.
Expect tantrums, naps, and ravenous hunger after school. They are exhausted when they get home, rightfully so. Our basic strategy is snack immediately and chill out time of their choosing (usually some TV). Maybe even some cuddling. I don't even ask too much about their day (we wait until diner)...just veg time.
Bedtime! Early bedtime! After dinner we might do something...play outside, walk, game, or a quick TV show (if nothing was watched earlier). But then it is bedtime. If they haven't dropped before dinner, by 730pm, the younger ones are drifting off. Don't want to sleep that early, read as much as you want in your bed (this usually amounts to 5-10mins).
As I am very busy as well the first few weeks of school, I try hard to plan dinners ahead so we can eat together and eat well. And have some good breakfast choices on hand for the mornings.
Its take some time but it will fall into rhythm.