DD got her first bottle at 4 weeks; she was really confused at first. The look on her face was hilarious. Keep trying and remember to use the slowest flow nipple.
Pumping only once a day might not be enough when you go back to work. I pump for each feeding I miss (twice a day). You need to pump enough times to keep up your supply. If you can't pump more often at work, you should pump at home and on your days off too. Often I don't quite make enough at work and have to pump again at home.
I made the nipple mistake without realizing it until after she drank 6oz of br. milk in like 5 minutes!!! it was a moderate flow nipple...oops- i have since fixed it.
I plan on pumping before work and at work and at night again if i have to. i would love to pump 2 or 3 times at work, but it just isn't going to happen. I don't get those two 15 min breaks that one is supposed to get. so lunch time is it! I guess i'll just have to wait and see how it goes. i really wanted to stay away from formula for as long as possible.