Supplementing?

Nickol
I'm 3 days pp. Baby was 7lbs 1 oz at birth. Now he is 6 lbs 3 oz. At what point should I consider supplementing? I think my milk just came I'm too. I'm a ftm so not confident at breastfeeding yet. The nurses have said that the baby is healthy. No concerns about his out put. Any advice or suggestions would be helpful.