PLEASE HELP! Breastfeeding/pumping problems

Hailey
Please help me get some piece of mind!!! So my LO is now a week and a day old- yesterday and day before I noticed she only ate for about 5-10minutes...she was born 2 weeks early and a sleepy eater in the hospital with a little jaundice, but it was only a little bit so they sent us home without having to do a billi light or anything and was getting better out first pediatrician visit....ANYWAYS I noticed her feedings being very short I came to the conclusion that my let down was to fast for her so I started pumping yesterday (only pumping once a day) So yesterday was the first day, I pumped after her feeding (ate for 7-10 minutes)for about 15 minutes and got 4oz!!! Great right? I sure thought so, it gave me piece of mind that I was making enough....and after pumping she began to eat for a longer stretch of time, resulting in more hindmilk so her poops became bigger AND more yellow....tha piece of mind just stopped though 😭... She has had 5 poopy diapers today and 4 wet diapers but I went to pump (second time ever) after her feeding on one breast for about 20 minutes and only got a 1/2 oz.....I'm so worried I'm not making enough for her.....I double pump btw. Please help this worried FTM....TIA😔💕