feeling frustrated.. not producing enough milk

Rebekka
Well my baby is 6 days old today. 
I wanted to exclusively breastfeed.. but my milk hasn't really come in yet. I have some but the amount that he is eating he dries me up fast! 
On day 3 he only had one wet diaper in 24 hours so the nurses (that helped me during delivery) told me to supplement. 
Well each time I supplement he eats between 30-60 ml. 
I feel like I failed! I am beyond frustrated and sad that I have to supplement. 
I have a nurse coming tomorrow to check out my situation and come for a home visit. She had told me on the phone to reduce how much I am supplementing.. She said max 30 ml a feeding 
My question is if your baby was hungry still after eating would you supplement them until they stopped crying and looking for food? I tried to only give him 30 ml but he cried and cried and I gave in. 
I feel like if he is hungry I feed him! 
Do I listen to my mommy instincts or listen to this nurse? Who honestly has no idea how much milk I have..