So my newborn is 8 days olds. He literally will not sleep at night, his fine in the day. To me it looks like he gets really bad stomach ache at night as he always pulls his legs up and crying. He hasn't done a poop for last couple of days which I'm sure is making him so uncomfortable. Should I consider changing his milk? He is bottle fed. We have just changed from the instant milk to the powder, could this of upset his stomach? Any help appreciated