Well, if it makes you feel any better, if my Dad was still around he'd tell you that I missed 16 times in one day. I'll admit to 11 times. I was about 15, had my Marlin 35 Rem, and the dogs ran maybe 10 deer past me. It was in Louisiana and on the edge of a slough and with all the deer splashing and me shooting and dogs yelping, I guess I got carried away with the moment. I even had time to reload. I did kill deer with first shot and last shot, though Dad always left that out of the story. I always wanted to be a legendary deer hunter, but not for the reason I became famous in the family.
My guess is that on the first shot you might have shot high and knocked meat and hair off just above the spine. Second shot sounds like a shot high in the leg. It happens.
And did you say that you had a scope on the rifle or not? When Dad, brother, and I all got our lever actions, I was the only one that refused a scope. That was a mistake. My deer killing efficiency went way up with the addition of a scope.