Gassy spitty baby

Feeling frustrated for my 3.5 month old. She is formula fed, one of the off brands that is like similac proadvance. She has struggled with excessive spit up for a few months now- off and on. Ruled out reflux. Spit and gassiness are her symtpoms. But when she has bad days, she is spitting after and during every feed, going through a laundry basket of spit rags a day. Pedi keeps saying shell grow out of it. At what point do i consider a different formula?