We seem to be in the very beginning of the 4-month sleep regression, so I'm trying to learn what I can. Here's the background:
C was born at 36 weeks, 3 days, so is technically a preemie, but he was well over 5 lbs and is growing well.
He started sleeping through the night on his own at 13.5 weeks; usually 8-9 p.m. until 6-7 a.m.
He nurses or gets breast milk in a bottle 5x/day during his waking hours - he doesn't nurse during the night any more.
He naps usually 3x/day, first nap is around 3 hours, 2nd is 2 hours, 3rd is a catnap.
He always sleeps in his crib (unless we are out of the house, then he sleeps in his car seat), and we put him down drowsy, but awake, swaddled & with a paci.
He is 4 months old & got his 4-month shots on Monday.
For the last 2 nights he has woken up 3+ times really unhappy. Usually if I give him his paci he settles almost immediately, but I'm still having to get up with him each time he wakes, and after even two nights, I can tell this is going to get really old really quickly.
To make matters even more fun, we leave on Saturday for a week-long vacation.

Any suggestions?