Newborn constantly vomiting/spitting up

Tabatha

My baby is 4 weeks and is constantly spitting up and vomiting breast milk.I burp and give a few ounces 2-3 per feeding and have him sit up right when I feed and keep him that way for awhile before I lay down. He’s gaining weight and his little legs are chubby lol. I’m not worried about that it’s just disgusting having to clean baby and myself up all day long 😭 is anyone experiencing this? What do I do? Is something wrong with my milk?