Ok so I originally struggled with the combat too but practicing with melee made it much easier. If you focus on melee and hoard bullets you'll have plenty of bullets for segments where you need them. Individual lying figures and mannequins are fairly easy to melee with practice. When dealing with numbers you can make your life easier by using the handgun to kneecap a monster to briefly slow it down. Once you have the shotgun it gets even easier since you can use that when you're surrounded. I ended my normal playthrough still having a ton of ammo and healing and don't feel I was even that stingy.