Yet another sleep-related question.
My baby is five weeks old. He sleeps like a champ at night - he'll go down around 10 or 11 pm, wake up for a feeding or two (and sometimes we even have to wake him), and will usually be up again around 6 or 7 am. Recently we've had success in putting him back to bed if he gets his last feed no later than by 6 am (starting time), and then he'll sleep until around 8 am or 8:30. We'll either put him down awake or drowsy or asleep, depending on the state he's in - it doesn't seem to matter too much.
Napping during day, however, is a complete other business. Starting in his second week, he'd simply refuse to go to sleep. If we attempt to put him to bed, he'll cry hysterically until we take him out of bed again; shushing and rocking and what have you not won't help. He will (mostly) sleep when carried around in a baby carrier or in his pram. This means that he'll get about 8-12 hours of sleep per day at most.
I would expect him to be overtired; but actually, he seems quite happy to be awake, and he's not fussy or cranky unless we attempt to put him to bed. He also has no problem at all staying awake for long stretches of time like an eight hour stretch. I've tried swaddling, to no avail (he enjoys sleeping with his arms above his shoulders, so I can see why would hate swaddling); I've asked the local children's services, who basically responded by saying 'well, if he's thriving and seems to be happy, then there's no reason to worry' - but I can't imagine that sleeping this little is healthy for him, and I also worry what this means for his future sleeping habits (and honestly, I could use a break as well).
We fed him on demand within 3 - 4 hours until last week; we then decided to introduce a fixed three hour schedule. We noticed that after three hours he isn't really hungry enough, so we just started stretching that to a four hour schedule. He seems to do fine health-wise - he was born with 3 kg, and gained 1.2 kg within four weeks.
Any ideas? Anything that I'm missing?