I had a hard time pumping when I went back to work, also. I would try every day at work, and my milk would fill in, and sometimes I'd get a little out, but i did struggle, even when it would fill in enough to leak into my clothing. ugh.
What I did do was to pump one side when I got home and my daughter was nursing on the other. Then I let her suck on the side I pumped to finish getting the milk out. I did the same thing at night, when she woke up to nurse. And that nighttime pumping, combined with the afterwork pumping time, gave me enough.
the other thing I did was to use a NUK nipple on the bottles at daycare, because they mirrored the human nipple, and it kept the baby's muscles up for nursing, instead of feeding the milk too easily. that was 26 years ago -- and I'm sure there are many more options out there for "exercising" type of nipples today -- and you'll get much better advice on that from your peers here.
I would note that it does take a little time to get the let-down coming, and probably your stress of the balancing act, the frustration with pumping, your fear that you might not have enough milk, and that nagging sense of worry, or "not being good enough" may also be hanging in your head when you sit down to nurse. Nursing is different from bottle feeding. It's cuddlier and more relational than bottle feeding, and it does take more effort and more muscle on the part of the baby. don't worry if your child starts to nurse, then stops and looks at you. Then tries again. Some of that is reaffirming the relationship. smile and look her in the eye and reassure her. (and you !) And let her try again. she'll catch on. And the more she nurses, the more milk you'll have, so you'll notice that it's harder to live without her on Monday at work, than on Friday at work, but overall, your milk supply should adjust to the demands. And if not, she is 5 months old. At 6 months she'll be starting to eat cereal and then other foods. You've done well to balance the act of nursing and being a working mom. You gave her the first 5 months, almost 6 of her life, to have the healthiest food known to humanity. You have done a great job, Mom. Remember that nursing is an "on demand" business, sometimes moms want to stop before the kids do, and sometimes the kids are ready to give us up before we are ready to stop. neither is a failure. It just happens. Of my 4 kids, my oldest nursed the longest, which was only 1 year, and she and I have the testiest relationship of all 4. The other three nursed less than that, due to stress demands on my time at work, and convenience for the babysitters. Whether you stop nursing sooner or later really won't impact the quality of your relationship with your child over time. Just keep loving her ! She's a wonderful gift and you are a wonderful gift to her as well !!