Have a 1 week old and using supplemental formula while breastfeeding


So I’m trying my best to breastfeed my daughter who’s a week old tomorrow. It’s still painful at times during feedings. We also have a 2 1/2 yr old boy. I try to pump as much as I can as well. I’ve been using supplemental formula as well because I feel like she isn’t getting enough after we took her for her weight check she was down from her birth weight of 5lbs 15 to 5lbs 6oz. We asked the pediatrician if it’s ok and he said yes, sometimes my husband feeds her the formula at night too so he can help out. I pump maybe an ounce every 2-3 hours when I do pump. I’m gonna try to breastfeed until I go back to work at least and pump as much as I can I’m just afraid I won’t produce enough milk and may switch to formula... have any of you been in the same boat??