Drowning in spit up

Ma
Does anyone else's babies spit up a lot? Mine is 6 weeks old and will spit up off and on for 3 hours between feedings. Just switched her formula to Gerber Soothe from Enfamil Gentlease, and it hasn't helped 😢 she doesn't seem to be in too much pain (just gassy fussiness). Anyone have any advise? Yes, I burp her and keep her upright, and she's on Zantac for reflux.