Has anyone have a 5 week old that's still jaundice? ?

So I took my 4 week old in for his month check up,and his pediatrician said he was still jaundice..which i couldn't even tell..a lil in his eyes,but I know that's the last place it leaves.he said in breast fed babies it's usually gone by 4 weeks..so he had to get his biliruben tested,then put on formula for 48 hours,then tested again.he said if his numbers didn't go down drastically,then he might have a liver problem. I called today to find out the results,and he wasn't in, but a nurse said that his first biliruben was at and 11 something,and after the 48 hours on formula it was down to 9 something. Not sure if that's a drastic amout? Cuz on the 1st he had been tested and he was at 17.9 I believe,but he was peeing and pooping really good,so they didn't put him under a light.then on the 4th he was tested and it was at a 15 something. So 3 1/2 weeks later it goes down 4 points,but after the formula it went down 2 points in 2 days..so is that good? I dunno,I'm just worried! Don't want my lil man to have a liver problem!! Anyone been thru this???