Problems with Pumping

My pediatrician requested that I introduce a bottle to my DD when she was 3
weeks old (she's now nearly 6 weeks old).* We had no problems with nipple
confusion, and she continues to nurse like a little champ (although the first
week was tough) while my DH gives her a bottle every night.*

I purchased a Purely Yours pump, and set off to build a freezer stash along
with the 4 oz that my DH gives her at night.* My problem is pumping during the
time that she's getting her bottle.* Am I just having problems with the let
down reflex?* I'm only able to get a maximum of 1 ounce out of each breast!*
While nursing my DD, I usually pump an ounce out of the opposite breast, and
have no problems getting that while also satisfying DD's appetite.* I pump more
in the middle of the night as my breasts are usually fuller, and get between
1.5 and 3 ounces out of one breast.*

I was hoping that my problems with pumping without her there was a learning
curve, but after nearly 3 weeks of this, I'm still not having a satisfying full
pumping session.* I'm terrified that when I return to work in another 6 weeks,
that the poor performance from pumping will continue and my milk production
will decline.* I've tried relaxing before pumping, keeping a picture of DD
nearby, having a snack and water beforehand, and nothing seems to work.* Am I
doomed?

Kymmi