lactogen vs nan vs emfamil a+ (which one is best vote) suggest and also tell why

Annie
hi everyone my baby is 7 weeks now...i try giving him my milk though i dont have much....so i do give him formulas currently giving him lactogen 1 but i think its making him gassy....thinking of giving him enfamil a+ but i have also heard good things about Nan...please help me out here with my little one....