Breastfeeding

Okay I go back to work next week I've been nursing my baby and I'd only pump Once s day and let dad feed her then or if I went somewhere I'd pump but I just started pumping more and saving it for daycare I have enough for one day but I don't think I can get the amount I need in one day am I going to have to stitch to formula or if I do can I still nurse at home and keep pumping at work a do half in half for daycare would this upset babies tummy? I want to keep nursing as long as I can I really don't want to switch to formula