Congratulations on the deer. I want to add... you did everything right. You knew your load, your ranges, and was willing to wait for just that perfect shot. The result was of course a bang flop.
Many hunters have to remind themselves of the importance of one shot, one kill. Its funny, even center fire hunters make a fatal mistake and take shots they are not ready for. It results in a wounded deer, a nasty tracking job sometimes, and feeding coyotes.