[CLIENT POSTGAME] No Score?

So I played a game, Teemo top (yeah I know you hate me), vs Trynd. Everything went super well for the game, 21 kills, 4 deaths, 13 assists, won the game, biggest killing spree of 9, largest multikill of 3, the only person with more kills or even dmg to champs was the opposing teams Draven with a score of 29/12/3. So really really good game, not gonna play again for today cause that was great. In the stats screen, however, I have a thing that says xp gained 285, and no letter score. Its not that it was a mediocre or bad one like an A or a B, but there was none. And 285 xp seems like its not a lot at all. So no S, even though it seems like it would be one, the normal base xp amount, and most importantly, no chest so I can get blue crap in this stupid league "economy" that was set up where chests and leveling are the only way to get the blue crap. Sorry, I am a bit annoyed. Can anyone help me out?