You've made it pretty clear that you killed it clean and took good care of the carcass. That is very important with antelope. In my experience, and I'm expanding that with the experience of my parents, who have been taking 2-3 antelope apiece for years and years, antelope is prime eating. We all rate it better than deer (whitetail or muley), and on a par with elk, although not similar in flavor.

That said, my parents swear that no antelope ever tastes gnarly unless the hunter did something wrong in killing and caring for the meat. I believed that until I went on my first antelope hunt a couple years back. I killed two does and a really big buck. The does tasted perfect, but the buck was atrocious! My parents grilled me hard about the kill, but I dropped him in his bed and had him quartered (I had to backpack him out 3 miles) immediately on cool day, and in a meat cooler within 6 hours. He tasted like he'd been eating sulphur. I can only attribute his rank taste to some peculiar food preference, like a human who insists on eating anchovies. (Not that I've ever eaten a human.)

Sometimes, rarely, a given antelope will just have that flavor. Remember, any antelope has an exotic flavor not quite like any other game animal in this country.