For the first few days, your boobs (actually, they already are) produce colostrum. It's very high in vitamins and a few other things, but not very filling. It's not meant to be filling. It's meant to penetrate and remove all the sludge from your baby's digestive tract (the 'meconium'). Meconium prevents things from absorbing, it protects the GI tract from a lot of things, and one of its functions is to keep it from functioning until it needs to. All the nutrients in utero your baby recieved are from the cord, but afterward it's the GI tract. So colostrum is meant to get things started. It's okay that it's not filling, because not very much bulk would get absorbed anyways. However, a lot of moms get freaked out because it seems like the baby wants to nurse all the time and seems 'hungry' and fussy. For some stupid reason, nurses and doctors sometimes push formula supplementation or sugar water at this time. I say "stupid reason" because it IS stupid. For the following reasons:
1. During the last few weeks of gestation, your baby doesn't develop so much as pack on some pounds. They get a very tiny amount of fat storage. That is meant, in my and many others' opinions, to make up for the lack of fiber and fat in colostrum. It's very normal, even for formula fed babies, to lose weight at first. The reason that formula fed babies lose weight, it is surmised, is because it takes a lot longer for the meconium to pass out and, if you'll remember, meconium is a barrier to absorption. Anyways, if your baby loses a few ounces, tThis doesn't mean you are doing something wrong or there is something wrong with your colostrum or milk. It's normal. You're not starving them. If there is dramatic weight loss, that's an indication that something is going wrong. But unless it's dramatic, you're fine.
2. Your baby wants to nurse all the time (or may not, especially if the baby is still drugged from birth if you use painkillers like demerol or epidurals) and that's GOOD. The more your baby nurses, the more and higher quality milk you will produce and sooner too, which your baby will love you for. Milk is basically a supply and demand thing. It takes generally 2-5 days for your milk to come in, although it could take as long as a week I've heard. Also, birth is somewhat traumatic for the baby too. Sucking on something is very comforting for babies. So if you're freaked out that the baby is using you as a pacifier, don't be. All that sucking is, first of all, helping your uterus clamp off the bleeding and go back to the right size faster which is great for you because it means less complications and blood loss, it's helping you loose that weight (part of the weight you gain in pregnancy is fat stores for breastfeeding, especially for those first few weeks), and it's bringing in your milk. Something that can really harm this process is introducing a supplemental bottle or a pacifier at this stage. It can cause nipple confusion, and your baby really doesn't NEED the formula right now. He/she needs to get rid of all that yucky meconium before the baby can even absorb most of the formula anyways. Incidentally, the sucking and resulting peristalsis (movement of the GI tract) helps get rid of the meconium too, but not as fast or effectively as colostrum. Oh, it helps your nipples toughen up too :D I basically spent two days with a baby attached to me :) It really wasn't that bad, or such a large sacrifice. As soon as my milk came in (day three, I believe) she stopped wanting to suck ALL the time, and settled into her own routine of eating every few hours. :)
3. Generally, you want to wait as long as possible to introduce pacifiers and bottles if you plan on using them. Doctors say 2 weeks, boob_nazis say 4-6. :D Anything earlier can, like I said, lead to something called nipple confusion. Believe it or not, babies don't naturally always know how to latch on to your breast perfectly and coordinate the suck-swallow and just how to do it. It's very instinctive, but it's also a learning process for both mom and baby. So if you introduce an artificial nipple when they are still trying to figure it out, they may get confused and not suck effectively at either or prefer one to the other, and usually the preference leans toward the artificial nipple because it's easier to suck and produce something from it. ESPECIALLY if you are having issues that relate to how the baby latches or lazy suck or anything like that, DON'T introduce anything artificial until you fix it. If not, I'd wait at least until your milk came in before introducing a pacifier if you plan on using one. :)
4. If your baby is fussy, he/she may not be hungry so much as wanting comfort. Recall that the baby just got uncomfortably squeezed through a very narrow passage, or at least taken from a fluid, warm, comforting environment to an environment full of lights, sounds, and air. Babies suck for comfort. They naturally will root for your breast for comfort, even if they aren't hungry. And sometimes, they will latch on, suck a bit, then get mad and unlatch and tell you all about it :). Either you have an impatient baby, or he/she is just expressing how he/she feels about that whole process. It's okay. You are not, repeat, starving your child. :) Babies can be really fussy those first few days, and no wonder! It's most likely not hunger related. Remember, their digestive system is just waking up and figuring it out.
ETA: One more thing about colostrum that's important to remember. Your breasts won't feel full of it, and you probably won't feel it come out at all. Colostrum doesn't 'let down' like milk does, nor does it swell your ducts to mammoth proportions :) This doesn't mean there is nothing there. One sign to look for is hearing your baby swallow. At this point she probably won't swallow after every suck. But every once in awhile you should hear a swallow. Also, she should continue to have pee diapers. If she stops having pee diapers, or they get really stinky and dark, and her fontanels and eyes look sunken, that's a sign of dehydration. And of course, look for the meconium. It's very sticky, tarry, and greenish. Arianna's was DARK green. So don't think you have nothing because you don't feel it; you do. :)
I can think of more reasons, but I just wanted you to be at least basically informed so that no one could cast seeds of doubt onto your breastfeeding relationship in those first few days. In a nutshell: you're not starving your baby, formula and sugar water wouldn't do your baby any good anyways, you might end up with nipple confusion which you don't want if you are trying for a successful breastfeeding relationship, and babies nurse for comfort too. :)