PUMPING & BREASTFEEDING?🍼🍼🍼🍼

My lo is 18 days old today! I’ve been exclusively breast feeding him since he’s been born but I want to start pumping so that dad can do feedings and I can leave the house for longer than an hour. I have some milk saved from catching letdown with my Haakaa silicone pump (about 30 oz saved from that) and I have a spectra pump but when I use that I only get like a half oz.. is there a way to increase this? How often should I pump to increase the supply with the pump? I hear oatmeal is good for increasing supply, does any brand or kind help? My LO is getting enough milk when nursing so it’s stressful that the pump isn’t doing anything. I really want pumping to work so any advice is helpful and so appreciated 😩