How do I know how much milk I should be producing

Hi there, I am a new mom, my son is 8 days old. When we left the hospital and had our check up with the pediatrician my baby had lost a little more than 10% of his birth weight(7.9lbs to 6.9lbs). Naturally I was upset and heartbroken that I failed as a mother. So they put us on formula and had me syringe feed 4mls from my breast and pump 15-20min every feeding. Naturally that became exhausting to do every 2-3 hrs. My milk is in now and in one pump I can produce about an ounce (I did 5 min let down mode and switched to regular pump 5 min back and forth) at the last weight check the lactation consultants said I could start to ween off formula and breast feed more but my frustration is that the stupid formula nipple is fast and nothing like a real nipple that when I try to breast feed he gets frustrated because he has to do the work. My fear is that I take him off formula and he isn’t getting enough milk. Is an ounce to 2 ounces depending on if he was at the breast beforehand, a normal amount for 20 min? I am going to switch up the pump mode to do 1 min let down and 19 regular mode and see what that looks like. I’m just frustrated because my goal was to breast feed and introducing formula in that bottle it comes in is ruining that.