Been there done that buddy!! I would say give him a lot of time. If you did in fact shoot him in the guts, he will start getting sick and bed down. Chances are, if you let him bed down and stiffen up, you can sneak in there tomorrow morning and find him beded, possibly dead. Take you time, look for the arrow first. Though mine wasn't a gut shot, my deer went a long way before I found him. Look for as many clues as possible in the area you shot him, and in the direction you went. It will give you a better picture of what happened and help you make a choice of what to do next.

Good luck, I know how you feel! I hope you get him in the morning!!