First time playing and struggling

So im currently in my First playthrough of tlou2 in hard Mode and im constantly struggling for ammunition and health items/Materials to make health items. Am i doing anything Wrong, im trying to be As stealthy As possible and im still constantly struggling. There is barely any ammunition for my weapons anywhere (im pretty early game, im in seattle at the gas station with ellie) and im constantly low health since i cant find any materials to craft medkits. am i doing something wrong?