My DS is 13 weeks today and I am still not sure I have him figured out

Ped has me giving him prevacid now for reflux although he does not arch his back after eating, he regurgitates food a lot and squirms, fusses and tenses up after feeding most the time and foams at the mouth after. They are trying the acid reflux med for him bc they think he may have GERD and he is down to having only one or two feedings a day when he acts like this and the others he is fine after he eats. I guess that means he does need the med and it's working? Also he had terrible gas since birth and would curl into a ball and cry a lot just after eating and also between feedings and would cry when he passed gas sometimes so he is now on nutramigen and he has zero gas now and his belly is not distended like before and he no longer needs juice and water to get him to poo every day, but his poo is liquid. I guess that's better than getting backed up and having the gas issues right?
Re: ? for reflux and/or hypoallergenic formula users