I also only play single player, and whilst there are some aspects of this game that appear to be weighted slightly towards the multiplayer genre as far as balance, I think you must have been super unlucky to be struggling as much as you stated here.
With only one point in Boom! Headshot, and one point in Hidden Strike, stone arrows were comfortably able to keep me safe, at distance, as long as I opened with a crouch shot, especially when hunting at night. An iron reinforced club as backup to land a single finishing blow if anything made it past my onslaughts and I don't believe I had taken a single point of damage before Day 7 horde. After that I'll admit I got cocky and reckless, but thats my fault not the games.
I had looted enough POI's to have more than one full stack of Steel arrows looted which I saved for the horde, found 3 anvils in working stiffs boxes, along with a working forge at my trader, I had crafted 500 iron arrowheads, and kept them back to only be used from days 8-14.
Admittedly I play 90 min days, so reaching level 25 by day 7 was a breeze, even though I wasn't deliberately power-levelling by any means. Going outside and shooting things from a safe distance with stone arrows, whilst predominantly sneaking is a powerful, safe and easy strategy for the early days of the game.
Learn to love the burnt forest biome, the zombies keep themselves nicely lit as easy target practice at night, and also super easy to see them long before they can see you. Shoot them once from distance and they will come running to roughly where you were when you fired, and they just stop. As long as you've to maybe 7 or 8 blocks away, you have an easy headshot.
Even more so for the dungeon POIs where it becomes quite obvious where the 'jump-scares' are going to be coming from and sneaking is able to pull one zambie at a time with no drama (except ferals, but that requires a bit more care - and a change of underwear occasionally - but they are also few and far between in early days). It is possible to sneak shoot the slatted doors that often hide the zeds from the far side of the room, which breaks the door and doesn't wake the zombie. Easy headshot, which knocks them down, second headshot when they get up and its dead. Maybe need a third/fourth headshot for big Moe/Bertha, but they move so slowly this is still easy.
Once you've got your iron arrowheads (fired from a dyed Compound bow - not even remotely difficult to find in loot), and a couple of points in Perception, almost all of the zombies (warrior level) are one-shot dead if you land a crouch headshot, including screamers, which saves a lot of night-time aggro once your forges are all burning away. Get used to the arrow drop and this is easy too. You'll never run into stamina issues after the first few days, and there are plenty of boars/rabbits/chickens/deer around to keep up with your food needs. Eggs are a little rare, but if you're going hardcore bow mode then you never stop looting birds nests anyway (currently sitting on a chest full of just over 1000 feathers).
If you wanna stick with the bow as it sounds like you do, make the most of it by dabbling a little in stealth too, and you may find you'll never touch a gun again (except maybe on horde nights). Its hella fun, and super safe!!