I think Daddy hit on something yesterday when he said Cale eats every 2 hours. Cale does that at night too. Well, mostly. His longest sleep is the first round, and that's when we feed him baby food before I nurse him to sleep (two kinds of food, and sometimes he sleeps 4 hours). Then on the better nights, he cries about every 2 hours, and I can nurse him back to sleep in 30 minutes (so I can sleep almost 1:30 out of every 2 hours). On bad nights, it's an hour to get him asleep, and he sometimes wakes the second he touches his crib.
I'm going to ponder better ways to fill his tummy. Although he usually has gas (often enough silent, and I feel it when my hand is on his butt, makes me suspect that he might have gas when my hand isn't there) when he wakes up. Hmm. So I need to reduce his gas and increase how much is in his tummy, and then I can sleep again. Hmm. Hoping for ideas to jump into my sleep-deprived brain.