The only thing I see you did wrong isletting a slightly bad shot outweigh the harvest of a fine buck.You completed the task by sticking withit and finding your game. You are taking it WAAYYY too hard.
You want meat? I'm sure there are plenty of local folks that would be more than happy to share their harvest with you. It would be a crying shame and a complete dishonor to that buck to stick his rack away because you are too obsessed in your pity party. Man-up already. That's why they call it 'hunting' and not 'killing'.