Thank you all for the encouragement!
We survived our first week. It definitely got better. After a lot of good conversations with the daycare, we got them to taper his A time to 2/2.5 hours. It's still a bit long for him, but he was getting at least 1 long nap by thursday and friday (1.5-2 hours). And best of all, he was less of a zombie by the time we got him home. Thankfully, he is still STTN as well.
Pumping has been interesting. My little guy eats a lot...usually 6oz a feed. I'm used to getting 6-8oz in my morning and evening pumping sessions, but during the day I'm only getting about 4-5 oz. My total oz with the AM and late night pumping is still a bit over what he is consuming, but it makes me a bit nervous that my supply will drop a touch and we'll have to supplement. I'm trying to get a pumping session for each missed feed, but sometimes timing just doesn't work when I come home so late and miss his last feed...I'd rather spend time finishing his night routine than pumping! Luckily I know that even if I end up supplementing, he's still getting some breastmilk, which is better than nothing.