Use the ones you have.
A quiver is 20 arrows, so even if you didn't have the foresight to have an extra quiver of arrows in the group, 20 arrows should last you the whole day.
Even if you have reached your first extra attack, fights last 3-4 rounds on average. It would be 3 fights before you run out those 20 arrows. Except that you recover about half, and those 10 arrows will be another 2 fights, since you recover half of those you use in fight number 4.
Most of the time, though, you don't hit anywhere near 5 fights before you long rest again and are able to make more arrows.