I can relate though I have no answers. My 4 1/2 month old is doing that, as well. He'd been sleeping 10 til 4, now is down at 8 but up at midnight, 3, 4... you name it. Sometimes he is hungry & will eat, other times, he nips & falls back to sleep. I would think if your babe is going til 4 or 5, that's good, I'd feed. I'm using the thinking that if it's been 4 hours or so, he could be hungry so I'll feed (& make sure he eats!) because I don't know if he is or not (though as a mom I know I'm supposed to know his cries.. I don't). If it's been an hour or 2, we're going to do pu/pd. Started last night. Wish us luck, ugh.