4 week old baby having regurgitation problems?

My son is four weeks old and is on formula. We started him off on S26 which we found he would bring back up even out of his nose. We changed him over to Nan formula for antireflux which is thicker and he seems to want to drink all the time plus he still tends to spit out some of it even an hour later. He is unsettled at night and need to know what i am doing wrong.. please help