How To Lower Bilirubin Level In An Infant?

Hi. My baby girl s bilirubin level was 12.8 at 3 days old and now she is 4 weeks old and still has yellow face and eye. So she had another blood test done and her level was 18. She is breast fed and she gained her weight from 2.8kg to 3.8kg. She poops and pee well. I m worried because the level went up and it seems pretty high to me. But her doctor told me to just keep what I ve been doing and we will check her again in a week to see if she is keep gaining weight and probably another blood test... I m not sure if its better to have some treatment done since she is 4weeks old and has high bilirubin level.. or unlike what doctor said at least give her some formula? (Doctor also said asian babys likely to have more Jaundice and have higher level?)