Breastmilk, is it okay??

My baby is 4 days old and just cannot latch onto me, not only that but up until last night and today I can only pump maybe 1 or 2 oz between both breasts everyday. Been trying to pump every time she eats her formula. I gave her the oz I pumped and she loved it, but when it was time for her next feeding I couldn’t even get half an oz for her, so formula it was. This happened again today. Is it okay for me to give her the oz or two and still formula feed?? Or is that going to upset her tummy and such... should I just stick to formula only since I can’t fully feed her breastmilk. I want her to benefit from breastmilk so bad!!