Acid reflux almost killed my baby.

My baby is 4 weeks old and has seemed to suffer from reflux for the past few days. He seems fussy and will burp up frequently, but has gained a pound a week since his birth although he wasn’t under weight to begin with. He weighs over 10lbs now, and was 7.3 when he was born. For the last two days he was crying for hours and seemed really uncomfortable, but still eating normally. Last night me and him were sitting together and he all of a sudden acted like he was choking. He turned red and was foaming and drool was running down his chin. Also, he went stiff and arched his back. I did the infant hemlick and my husband called 911. After a few seconds he was fine and was great the rest of the night. He hasn’t seemed to be bothered my reflux since. The paramedics said his lungs were great and he was perfect. I am calling Monday morning first thing to make an appointment with my doctor, but other than that what Can I do? I got gripe water and gas drops and that seems to help. Also, I’ve made sure to burp him and sit him upright.