I think ya did the right thing man, listened to your instinct. Always be sure of your target.
I know how ya feel though. 2 years ago me and my wife were hunting and right at dark out comes this deer. Foggy as all get out and I couldn't tell if it was the big 130-140'' deer we had seen pass earlier but couldn't get a clear shot. Till this day I know it was him cause the body was HUGE. But I just couldn't be sure. I'm glad I held fire though, who knows there's that .000001% chance someones donkey got loose and my minds eye thought it was a deer and I shot Eore. Never know.
Good luck, I'm sure you'll get a better chance.