Worried that my 1 week old has a cold 😫

I've read and talked to a nurse that both said a baby sounded congested is totally fine and don't worry. But his breathing just sounds so mucusy and congested I'm so worried. He coughs a couple times laying down at night. Maybe reflux???? He doesn't have a fever and is eating every four hours (formula fed) also is wetting diapers good.

Does anyone have any advice??