Sounds like a single lung hit. From what I have seen and heard is liver hit deer will run as hard as they can until the finally give out. That being said I shot a doe 3 years ago and only got one lung on a sharp quartering away angle. She did the same behavior as you described. I backed out and came back right before dark to look for her and spotted her still alive about 6 hours later.

I applaud your decision and from the way it sounds you will be adding a new trophy to your wall in the morning.