advice pls with formula

when i came home from the hospital my baby was on similac advanced pro but then i went to wic for the first time & they offered enfamil gentlease bc of his gas but it’s been about a week & a half & after every feeding he’s been excessively spitting it back up. even an hour or two after the feeding another mouthful of spit up comes out. i’ve tried burping him between ounces but he will still spit up with every burp & after. he’s 2 & a half weeks old. & he’s constantly fussy & crying which gentlease formula was suppose to help but didn’t. is it the formula that needs to be changed? also if anybody knows WIC rules will they change it to another kind they carry without a doctors note? thanks