Help ...

I breast and bottle feed my baby. He’s a week and 4 days, when he has a poop its yellowish / mustard color with seed like but when he poops it sounds explosive and has a stiff water consistency to it, it dosent have a horrible smell though . His anus is a little reddish. Can someone help and tell me something im very worried this is my first baby😥😥😥😰 what can be the cause of this or is it normal for his poop to be that way ?