Agreed, you hit it low in the chest, missed the heart and did the deer no real lasting damage.

Oddly, sadly, I did the exact same thing last year on a buck. I'm not real happy telling the story, but... I misjudged the range on an extremely cold (-10 degrees) day. The shot looked good, and the buck donkey-kicked before darting into heavy brush. I was celebrating as I approached the spot. I began tracking him and had good amounts of blood to follow in good tracking snow. Two hundred yards later I began to realize something was amiss, 'cause he was still going. Shortly thereafter, he cleared a barb wire fence on a bound that carried him 25-30 feet. I trailed him for 800 yards, with the blood eventually petering out to a single spot or two every 100 feet. I spotted him another 500 yards ahead, and he wasn't showing any signs in his walking motion of being hit. In fact he was chasing a doe around. He did stop occasionally to lick at his side, way low down. It was too open to get close enough for another shot (300 yards is my max), but I just walked up to them to make him run and check out his run for any signs of serious injury. He ran off with ease, clearly not hurt badly.

The rifle I used was a 270, the shot turned out to be 250 yards, and I bought a range finder this winter to try never to do that again.