Rank for S7... Here comes bronze hell again

So I won 7/10 games, carried most of them with yi (5/10) and one game with shyv lost my last 3 games two games because of trolls and one person afking at teh end. My mmr is mid silver, yet here I am back in bronze once again to fight against bronze hell. It took me almost the whole damn last season to just carry myself out against all the trolls and afkers, but now you are saying have to go back through it again. I know it saids everyone goes down a few steps in rank, but for me to take a whole division setback and be at the bottom of the barrel seems a bit much. I could accept like b2, but B4 from S4 really. I really though that placement if you won them, gets you a better placement because it does show you have improved from last year placement, which I only won 3/10, but evidently that does not matter. Why don't you guys just remove placement in rank and start everyone a division behind because it makes no damn sense to me why.

Someone Explain how my Shyv mmr went from 1254 to less than 1000 after placement, or my yi which was from 1400 to less than 1000. I had a 3.0 KDA with yi and a 4.0 shyv KDA, only played 2 games with shyv. something does not seem right at all here.