Hi My 37 Weeks Old Baby Boy Frequently Vomit After

Hi my 37 weeks old baby boy frequently vomit after the feed the content of the feed is just milk after feeding and during vomiting his feet turns blue for a short period of time and again after few mins his feet Gonna become normal do I need to worry about this issue he is on formula feed every third hourly 50 ml per feed his weight is 2.5 kg