i made the game in unity's regular resolution,  and only on the last day i ported it to 160 x 144, the problem is: i expected to loose quality on the sprites, but that didn't happen, instead the camera is too close!

Try rendering your game to a 160x144 render texter with your current camera.

Then make a second camera and a canvas set to "screen space - camera" . Add your render texture to a "raw image" component on that canvas (or a child of it), and have it fill the screen.

(Alternatively try changing the pixels per unit of your assets, but this may break other ways that your game is set up)