An arrow will come to a complete stop on a deer shoulder or richoche out away from vitals. You did the right thing. I'd go over the land next time you get a chance just to see if you can find the arrow. But in my experience and opinion if you feel you did a reasonable search and exhausted all evidence of trail then you did all you were bound to do. You backed out and let the deer have room to die and went back the next morning. You did a thorough tracking job. You lost a deer. That sums it up and nothing about that line of statements are wrong. Hell I hit a buck in the shoulder with a 150 grn hornady 30-06 load Sunday and it still made it 60 yards before it dropped. You hit yours with a broad head. lol It probably pulled it out with its teeth and ate it for breakfast while sitting on the top of the hill watching you crawl through the woods on your hands and knees. Sorry just kidding. But seriously I've been there too. It's not a good feeling but it happens. In my opinion any bowhunter that says they havent ever lost a deer is either lying or they haven't been bowhunting for very long. I wish you nothing but the best and I hope you find your arrow.