but it sounded like I shot through a watermelon
You are doing exactly what you're suppose to. Get out quiet, leave him completely alone, go back in good light and leave him all night.
The above quote tells me you have a good chance at a very dead deer.
Now tommorrow morning, when you recover him, take some really good field photos, I mean spend extra time making him look the trophy that he is, take many many more picture than you normally would - make it count and then go to
www.tinypic.com, upload then and post them.
I'm giving you an excellent chance at recovering this deer.