Is this bad?? Giving more formula than breast milk??

Soo my milk supply hasn’t been able to keep up with baby. I’m not nursing him from the breast I’m strictly just pumping only and feeding from a bottle. I started him on formula because I was only pumping like an ounce every 2 hours and now I’m lucky to get 5-6 ounces of milk pumped PER day. I figured i could give him a bottle of breast milk in the morning when he wakes up and a bottle of breast milk when he goes to bed so that I can hopefully get my supply back up. But I was wondering if this is okay?? Is it bad for him??