Are you breastfeeding at all or are you just pumping?
If you are breastfeeding and just pumping while you are at work during the day, then missing that night feeding is going to effect your supply. If you want to continue to exclusively breast feed (or give her only breast milk) you will have to continue to either breastfeed or pump at that night feeding.
If you are not breastfeeding, but pumping and giving breastmilk, then things are a little different. A lot of times the pump can't get out as much as a baby can, so you may have to end up supplementing with formula anyway if you can't get enough out with the pump (but this is just if you are pumping and NOT breastfeeding at all).
Are you having trouble with your pumping supply at night? It is very common to have less milk at night. If that is the case, any amount of breast milk your daughter gets is good. If you can't get enough out at night, give her the few ounces that you pump and then give her some extra formula. This is ONLY if you are exclusively pumping though. If you are breastfeeding her, then this is NOT a good idea because it is a good way to lose your supply.