PLEASE HELP! Pumping experts and BF pros needed

Just had my baby 5 days ago. I found out he has a tongue tie so breast feeding as been a struggle. He started to become jaundice and lost 9% of his body weight. I started pumping 3 days postpartum so I could spoon feed him and avoid nipple confusion but wasnt producing much so my sister leant me some of her breast milk. Spoon feeding wasnt seeming to work because he was still losing weight, so I tried feeding him with a bottle. He is taking a bottle now. Our routine is every 2 hours trying to get him to latch so he can keep interested in my nipple, then I feed him with the bottle, and then I pump as much as I can get out of each breast. I'm only expressing .5-1 ounces total with both breasts combined when pumping - which is just not enough for him anymore. I'm only feeding him as much as I'm able to pump per session because I don't want to run out, so hes hungry every hour now. I just got some premade formula for the night so I can keep adding to my supply of milk and hopefully increase my supply, and so that he can actually be fed the correct amount. Has anyone gone though anything similar? Is .5-1oz normal for 5 days PP? My milk came in 3 days PP which is also when I started pumping. Shouldn't it have picked up by now? Any suggestions or insight is greatly appreciated. Its been a rough few days.