Hi W.,
I don't want to hurt your feelings or anything, but I'm curious, why do you think your 12 week old son should be sleeping through the night? If your friends or doctor have said this, please don't listen to them; they are quite ignorant of growing babies. This is perfectly normal for him to NEED to eat through the night, for much longer than 12 weeks. He is not "discontent" or "demanding," as some people suggest. Babies have tiny stomachs and all they are digesting is milk, or formula milk--which does not take long to digest. Not only that, but babies go through periods of growth spurts in which they need all of those extra calories for growth and development--ESPECIALLY for the development of their brains.
If you need more rest, I suggest taking naps with the children during the day, or going to bed earlier at night. I'm sorry to say that sleep deprivation is just a part of parenthood during this time period. I guess the thing that helped me get through the exhausting first years was the fact that I could be grateful that I had the ability to feed my children all of the nutrients they ever needed in order to become healthy, intelligent adults. Rarely in the US do we ever have to worry about our children becoming mentally retarded and failing to develop properly for lack of protein and a good diet, as many impoverished children do, who suffer around the world.
Withholding food from any baby is unnecessary and quite frankly, neglectful. So please be careful that you do not put your sleep in front of your child's very crucial needs. Under exhaustion, I know it's hard to remember that our children only ever NEED us. And sometimes, sacrifice is the most loving thing we can do for our families. I have a song I sing to myself whenever I am having a hard time with all of the requirements of parenting...I hold my little baby, rock them back and forth and sing "Loving my baby, loving my baby."
Best of luck Mommy and Congrats on that beautiful baby!
J