There is a walkthrough on discord
Salvaging that run is still possible, but it will be very hard. You'll need to get good at sneaking and dodging.
Hints:
The licker enemies with the very long tongues are blind. If you hold Shift to walk, they can only get you by running directly into you.
Shoes are not just fashionable, they also increase your speed. Save them for crowded places. You can't take them off to save their durability, but in a pinch, you can walk to prevent durability loss.
I've done a no-shots-fired (until the boss fight) virgin run. And by virgin I mean not even getting grabbed (scripted mandatory scenes don't count, as they don't give sex EXP anyway).
It won't be easy, but you can do it. I believe in you! lol
Edit: Also don't worry about no ammo before the boss. You'll have a technically unlimited supply.