baby never seems to get full -bfing?

Doesn't sound like a problem. She is gaining weight at a good pace. Try to relax about it. Make sure you are getting enough nutrition yourself and don't forget to stay hydrated.

Falling asleep is a cue that baby is done. There is no rule that states a baby must eat for any particular amount of time. They eat until full, then stop or fall asleep. Perhaps she is restless because she is done, but you keep sticking her back on. Some babies will "nibble" for quite some time, but not actually eat. And a bottle is faster, so she may be eating more than she intends, but not realize she is full (not pulling away because the signal hasn't had time to get from her tummy to her brain that she is full)

A pump doesn't get as much put as your baby, and 4-6 oz is pretty good. So she's probably getting 6-8 oz or more at each feeding.

Spitting up means there is gas OR she has eaten more than her tummy can hold (I suspect in your case it's the later :)

Try these websites, they have lots of breastfeeding info. The first one is La Leche League (La Leche League is an international group of women who give mother-to-mother peer support. They are a wonderful resource for support and information and run support groups in cities all around the world) Contact a group in your area, they can help you more than quick internet answers. Or find a lactation consultant near you (the 3rd site can help you find one)

http://www.llli.org/nb.html?m=0,0,0

http://www.drjacknewman.com/

http://www.kellymom.com/

Babies always drink what they're needing, and by the sounds of things she's eating what she should be, perhaps a little over for her age. Five ounces at each feed is enough, and your breasts keep up with your child so your breast milk will increase when demand increases. Don't stress too much, she's putting on weight and she seems healthy.

However, I have known mothers to assume that the reason that their babies as restless is because they want more milk and need fed. Restless = bottle. Cranky = bottle. Crying = bottle. This is just not true. Some babies (and I'm including my two here), even at six weeks, want to be put down to play. Or just want sang to. Or taken out in the pram. Or need sleep. There are lots of reasons why your baby could be restless, and have nothing to do with being hungry. So perhaps if she's still fussy after feeding and you don't think she has wind, put her down to look about. Or take her out in the pram.

As my friend once told me, if all you see is boob, you'll want boob. Let your baby know that there's other ways of coping with being restless than eating, and you'll be setting her up good for the future.

Just FYI, I had low supply with my first baby, so I pumped a lot. With my second baby I had oversupply and donated milk to a milk bank.

I NEVER got 6 ounces pumping in one session. You have an abundant milk supply. Your baby is getting plenty of milk.

In addition to a possible growth spurt, she may have reflux. Reflux babies are fussy nursers, spit up frequently and larger quantities, cry after a feeding, and like to suckle for comfort - swallowing more milk soothes the "heartburn" feeling of the reflux, but having their tummies too full makes them reflux more, so it's a vicious cycle. Try keeping her elevated for 30 mins after a feeding (like sitting in a bouncy seat or carseat), or using a sleep wedge in the crib, or putting her in a vertical-style carrier (like a Bjorn or Moby Wrap). If it helps, you can check with the pediatrician about how to manage mild reflux.

What Julia said plus I also wanted to add that 6 weeks is prime time for a growth spurt so she is probably nursing frequently as a way to try to build up your milk supply.