MM Premier Rating, hello ??

Can someone tell me whats wrong with the rating in Premier ?

my complete match history i had 20+ kills on first place of my team 8 out of 9 times, carrying nearly every single game and im getting a rating of 1700 ???
my mates and also the enemys on 4k+ ratings dont have a single clue of the game and im getting 1.7k ?
whats wrong here, i dont understand...