Help me understand this freaking new ranked system!

I had bronze 2 by the end of season 6. I got exactly 5-5 on my placements getting bronze 4 (against an mmr of silver 2 consistently). Than after playing that one extra placement and WINNING i got bronze 5. I honestly am not upset about this that much because riot told us about the rank drop ahead of time but why in the world am I stil being ranked against silver 2 players which was the same mmr I played against throughout my promos. I read a post where a guy said that your rank will drop but your mmr remains, so you will get more LP per win. I do currently get 30 LP per win and lose 14 per loss. But is my mmr really up in silver 3ish area? So would that mean i would be silver 3 if it was still season 6?