D.L.
When I nursed and pumped with Owen I always pumped only one breast so the other was available and full of milk for him. I could also tried to pump when my milk production was highest, in the morning. And use the pump on a different breasts because the way it tells your body to make milk is not as effective as a baby nursing. Oh, and pump till it is empty (breast) so you ody will know to make more and so the bottle will have the protein filled hind milk as well. This is also why it is good to have a full feeding on one breast so they can get the hind milk.
All this helped me keep my milk production high and pumping was never too much of a hassle.