My son is now 11 weeks old and he is still not sleeping more than 3 hours at a stretch. He wakes up at night gassy and hungry and fussy about his diaper (disposables at night). But honestly, he doesn't seem miserable: he just seems up! Sometimes he eats an ounce before drifting off again, sometimes he gives a small burp and is fine. Sometimes I pick him up and he doesn't need anything--I just put him down in a different bassinet (in the living room, where I am sleeping) and he's straight back to sleep for another hour.
He doesn't have his days and nights switched, because when he wakes up during the day he wants to play and when he wakes up at night he just wants to go to sleep. He is mostly bottle-fed, and while we have tried feeding him a lot before bedtime he just doesn't eat much when we try to mimic cluster feeding. We give him gas drops at every feeding and have tried generic GentleEase as his formula (though he still eats Similac advance and Similac for Supplementation on occasion). He sleeps in a separate room from my husband and me, with white noise playing and in near-complete darkness.
We have a bedtime routine (starting between 8 and 9, finishing by 10.30): bathtime, massage, bottle and storytime. He always goes down for 2-3 hours after that, but then he wakes up and is up every 2 hours after that.