Re: Feeling uncertain....
hi mama, congratulations!!
the rule of thumb is that babies will take 1-1.5 oz per hour while away from mom. so if you're gone 9 hours (i'm guessing?) then you'd want to send 9-14 oz for the day. most caretakers over-feed babies, but it is definitely possible that she actually needs more than 9. most pumping moms need to pump extra times to make that amount, because we just don't respond to the pump as well. every 3 hours is ok, every 2 - 2.5 sometimes is better if you have the flexibility at work. other moms add a pump first thing in the morning (when yield tends to be highest), in the middle of the night (yuck, but we do what we have to do!), and on weekends.
it's definitely an excellent idea to nurse her as much as she wants in the evenings and overnights. in general, setting a schedule for nursing (like the every 3 hours your ped recommended) is a recipe for reduced supply. hardly any babies actually get hungry on exactly that schedule, and since demand = supply when it comes to milk, restricting demand by following a strict schedule often results in lower supply long-term. (also - extra evening nursing for a 9 weeker is generally NOT just for comfort, but also for calories!) especially when you're full-time working, the scheduling can result in a cycle of supplementation.
of course, any milk is better than none, and if you're willing to supplement and have maxed out the times you can pump, then you'll just have to wait and see how long your supply holds up. some moms might do fine with this pattern, but particularly since you're starting when your baby is so young, i would guess you will end up gradually increasing the supplements and decreasing the milk by 6 months, if you go that route.
also, pump output is a terrible indicator of supply. 3 oz per pump is normal, and not an indicator of what she's getting "from the tap".
good luck, hang in there!! we have all been there and hardly anyone enjoys pumping - it is WORK - but it is also worth it
Nursing, pumping, cloth-diapering, babywearing, working professor mama with the awesomest SAHD ever.