My S Grade

RIght after I loaded out of the game I was playing it said I got an S on Wukong going 14/4/6. I go to make my Wukong mastery 6 because it said I got a m6 shard and that would have been my last one, but when i got there it only had the shard i got from my last game which i got an S- in. SO I went back to my match history and it does not even show a grade for the game. Why did I not get a grade and why didn't I get a shard after the game? Is there a way for me to get the shard back without having to play more games?