My newborn is sleeping too much?

I have a week old baby boy. When I got discharged on friday he had to say 6 more hrs bcuz he had jaundice. So during the weekend I was really worried bcuz I noticed he looked really yellow including his eyes. I took him to the dr on monday and the dr told me to take him to get blood work done bcuz he did look yellow. So I took him and sure enough his jaundice level was at a 19 =( so they admitted him to the hospital and they said he had to stay 2 days. So it today they said it went down to a 14 and they discharged him. In the hospital he kept me up all night for those 2 days and he was constantly eating and pooping and peeing. Well today at home he has slept all day. I've had to wake him up to eat and when I do he doesn't eat as much as he usually does(breastfeeding). He hasn't really pooped since very early in the morning. He has peed though. Should I be concerned that he is sleeping so much? And that he hasn't pooped today? Has this ever happened to anyone with their baby just wanting to sleep? Or not poop?