Going back to work is a transistion you and your baby should make smoothly. As far as supplimenting with formula, you don't really need to. I don't know how old your daughter is, but you may have noticed that all of the sudden your baby might want to nurse constantly for a day or two and then go back to her normal routine. This is her way of building up your milk supply, without knowing it, your body is making more ounces per feeding after a nurse-a-thon day to meet her needs. Most babies get up and feed just a little at 4-5 am and then go back to sleep, this is your most productive time to get extra milk. After the baby feeds, put her back to bed and pump as much as you can get out and then let the pump pump you while you are dry for 5 minutes each breast, this will trigger your hormones to tell your body to make more next time. You can pump a little bit after each feeding. In the evening, have someone other than yourself feed the baby from a bottle, even if it's just a little breast milk or watered down breast milk to get her used to using a bottle. There ar many breast like options now for breastfed babies to use. During that feeding, go in another room and think about your baby being fed and pump away, pretty soon you will be able to pump in place of all feedings, and eventually you will even be able to pump just twice a day while you are at work and make enough for her. Example, if she normally drinks 3-4 ounces every 3 hours, then you will be able to pump 6-7 ounces every four hours. Get the good Gerber nursing pads and try to pump immediatly after feeling a let down so your bosy doesn't learn to ignore the cues that it's time to feed her. Bring a blankie with her smell on it, a picture of her or even a talking picture frame with her cry or coos on it to help stimulate your milk supply. Most of breastfeeding is the emotional ties that trigger our hormones to do the work. I remember driving somewhere and my milk let down, i couldn't figure out why since i had just fed my baby, and then i looked in the rear-view mirror and saw a woman walking with a stroller, i didn't even notice, but subconciously I did and my body was ready to feed a baby. Please contact La Leche League, they have chapters in all areas and the ladies there are WONDERFUL and will be available any time you need help or have questions. Pediatricians and OB's aren't always the best experts, try to get support as much as you can. Many bigger cities have working moms breastfeeding support groups and they really help, just knowing other women who are juggling the same schedules, workload and emotions as you is so beneficial to a mom. You can do it, you were meant to be able to feed your baby and using modern technology to get the same goodness in her is awesome. If you do have to resort to an emergency formula bottle or two, I would use Carnation good start with cultures, it is most like breast milk and is easiest to digest. Avoid water and juice bottles as this will only cause your milk supply to drop because baby will not be as hungry and even knowing that your baby doesn't need as much milk as you are producing can cause you to slow down your supply. Pump yourself dry at the end of each night, that will also help you store. I used the gerber breastmilk storage bags. I would pump a little, even just an ounce or two into a botttle, cap it and refridgerate it. Then the next little bit i would put into a different bottle. Once the milk is cool, you can put it all together in the storage bags and ziploc them shut and flat. Label them with a sharpee with the amount, and date. You can get these icecube storage containers that have a icecube tray on the top at walmart for a few bucks. They are the perfect size to store the milk bags in, they just line up like little files of milk. this method allowed me to store about 40 bags of milk in one small tray and the milk defrosted the quickest when stored flat, you don't want to microwave the milk because it will lose many of the good properties. if you have any other questions, feel free to email me at ____@____.com