cod - think you may be right about putting the playdates on hold for a bit. The school has already advised parents to only schedule birthday parties on Friday afternoons (school out at 12 that day) and weekends. Expect that parties and once a week swimming lessons may be as much as dd can handle.
Find it truly amazing to see that many mums have their 4 year old little darlings scheduled for after school activities most days of the week - ballet, art, music, drama, tennis, etc. Can't imagine that the kids will be able to cope with a schedule like that....and those same mums (who tend to be very competitive/accomplished) look at me as if I'm causing dd to "miss out" by not having her participate in endless activities.