Help ...

I have been giving my baby formula and Breast milk that I have stored. The Breast milk is running out and she perfers now the formula over the Breast milk.... I'm on antibiotics .. So I have been pumping and dumping I have 4 more days to go... What do I do if she refuses my milk when I'm done with my antibiotics ? I don't want her on formula it stresses me out having to dump 8oz every 3 hours while she drinks formula.