You are absolutely correct I think. Inexperience and adrenaline are very likely. Do let us know how they continue to work for you. Even the best of heads can have a bad day and loose a blade. Let us know if that happens anymore.

Also, just because it is season doesn't mean you shouldn't keep practicing your shots and be more patient on you shot selection. By that I mean wait until the deer turns and gives you the proper shot angle. You won't have to worry about bone as much.

Good luck!!