Which formula do you use for fussy baby?

My little one is 5 weeks old. I only breastfed for the first 2-3 weeks. I am now down to 1 bottle of breastmilk a day and have been using Earths Best formula. Baby is drinking 4oz every 3ish hrs. He is extremely gassy all the time, spit up 4x from one bottle this morning and refuses to be put down or he wakes up crying. I am also using gripe water at least 3-4x a day. I am having a hard time getting anything done because he will only sleep on me while being held. Spoke with pediatrician who said to try the sensitive formula which may help with the gas but not with the reflux if that's what's causing him to not want to be put down on his back. What type formula have you had luck with or do you recommend or have had good luck with? Thanks!