Newborn burping advice


I am a first time mom and today I experienced something that made me absolutely scared. My 4 day old baby gets a lot of gas and I burp him after each feeding but there is always gas around....sometimes when he sleeps, he wakes up because of gas but today he went all red and looked like he had some gas stuck so I got scared and started burping him and he looked like he was almost choking....I don’t want to see this again. How can I stop this from happening? Please help