Soo I got placed in silver 5..

I just finished my placement won 9 out of 10 and winning the first 7 games in a row. Only to get placed in silver 5? idk wtf is up with that. i was gold 4 last season and my mmr wasn't tanked either so wtf is up with that? I play my ass off only to get trolled and put into silver 5? My main account got placed in gold 3 after being plat 4 in preseason and i only won 5 out of the 10... like wtf? i mean silver 1 or 2 sure but silver 5????????????????????? bleh ranting. anyone else get fucked over? also its not going to be hard to get out of silver but i mean come on winning 9 out of 10 you'd think i'd get placed higher considering i wasn't bronze 5 last season or something.