Parents choice gentle/Enfamil

Has anyone tried walmart store brand (parents choice) of Enfamil gentle ease, my poor baby is always gassy and pushing like if he's constipated I've tried different baby formulas. And wondering if anyone has suggestions..my breast pump broke:( would rather give him my milk but it is also difficult too. He gets so frustrated trying to latch on. I also feel like im not making enough breast milk.. Makes me so sad not being able to help him. He's a little shrimp.. Baby formula is so expensive😮🍼