L.C.
Well, my first concern would be to ask you, according to whom is your baby not gaining enough weight? Those charts are based on an average of all american babies. Is your baby average? Ofcourse not! Perhaps you are of a different ethnicity than the "average" or you are taller. Who knows? Does your baby look healthy to you? Does she seem content? Remember, no one knows better than you what is best for your babe. You might try changing pedis if you dont trust yours 100%. You might try giving Kathy Truslow a call. She is ours and she is incredibly caring and i love her very much.
My next concern would be that a little one so young should not be on any sort of timed schedule for feeding. When my boy was a newborn he nursed about every 45 min. If you let your little one nurse more often you would get more milk and it would go strait to her- no need for pumps (man i hated mine) or concern about nipple confusion. Also, breast pumps are not really very good at stimulating more milk production. I think that our body is smarter than that. So i suggest just letting your little girl nurse more often. Our bodies are amazing and will, except very very rarely, always provide just what our babes need. If you are having a hard time finding more time to nurse i suggest trying one of the wraps that allows you to nurse with them in the wrap so that you are hands free. I used a Moby Wrap. I am a single mom. If i had not had my Moby i think i would have starved to death or worn drty clothes for the first 6 months, for lack of a chance to get anything done.
You might also try adjusting your diet. Are you getting enough fatty acids? Try foods like avocado, almonds, eggs. Be sure you are not 'dieting' in any way. If you feel your little one is not gaining enough weight, that means what you are eating is not proving enough fat and protein. Good luck, and just keep in mind that you know best, and your body will provide what she needs.