My hidden mmr is messed up, but how?

Hey peeps, even since I ranked from plat to dia the game put me in ascendant mmr. I havent played for like 2 ful episodes, and now that im back Im still in that elo. I got placed plat 3, but get teamed up with acendant and high dia.
I cant be usefull, since my aim has gone to shit.