It happens, we're throwing fake baits armed with sharp metal objects at fish. Eventually we accidentally hurt fish, it always sucks when it happens, but it isn't your fault. You did all you could do, which is what any responsible angler does. Plenty of fish are out there with one working eye and seem to do just fine, if it helps you feel a bit better.
I gill hooked 2 pike last weekend, I felt bad as well. They were slamming it so hard, I'd set the hook as quick as I could and they were both hooked bad regardless. I wound up keeping those ones.