First time use here for Desperate help

Megan • Megan💄 Ortho asst🦷 fur mom to two GSDs🐶 3 miscarriages 👼🏼 Gracie Mae🌺

I’m trying to figure out if I am producing enough milk for my little girl. She is only four days old but it seems like she Is constantly needing to eat during the night. During the day it seems to be OK every couple of hours so I just want to make sure that she is getting what she needs and if not I get it all straightened out. My question is how much should I get for my first pump session and my milk supply only coming in yesterday