You say you hit the deer 4" above the belly. If you shot from a treestand, and depending upon how high up you were, that COULD only be a grazing hit. I can't see how the arrow did not pass through, unless it also hit the offside front leg. Things are not always as they appear. You may have a better hit than you think.

Leaving the deer overnight was the best thing to do. Give it your best effort in the AM. I have seen good hits not leave much blood, so don't be discouraged. Put the time in to really scour the area. Don't discount tiny spots of cover in open areas. Wounded deer like to be able to see what is approaching.