When is infant spitting or ‘ throw up ‘ a lot ?

So I don’t know if I should call this spitting or throw up, my 5 weeks old baby has been spitting a lot after every feed, right after he pulls off the breast he will just sit there for a quick seconds and before I even take him to burp him he will spit he also make the grunting sound and will move his body as if he wiggles then he will spit, it does sound like the burping sound but with the liquid coming out. and it happens frequently. Should I be concern ? He still eats well but just spitting

Thanks