I feel for you. That sucks.
When you're ready to look on the bright side, it's that one C which makes all the As in life meaningful. And it's not even a failure, just an average. Fate is saving your below average grade for another experience -maybe that gas station attendant.....
And if you were doing it to impress/prove a point to someone who's gone/doesn't matter any more, that means you're now doing it to impress the one person who really does matter and who will always be there -you. So it's all good. Been there, done that, have a PhD.
Good on you, Bri, for sticking with it.