Im confused. Could somebody help?

Hi i'm Xilann and I joined League towards the tail end of season four, a couple months before they began changing the jungle (Spirit of the elder lizard was remove etc.) I got VERY lucky with my provisionals and ended up winning 7 out of 10 with almost no idea how to play the game. That landed me in gold five, I was ecstatic and I managed to maintain that rank until season 5 role along where I was currently maining Shaco in the pre-season, when the provisionals rolled along I (Obviously) lost most of my provisionals but still ended up in Bronze One. Realizing that my Gold 5 rank in season 4 was a total stroke of luck I have humbled down and actually taken the time to learn about the game. So in season five after continuously going up to silver and sinking back down (Several times) I felt I had played enough in the lower Elo to rise above the others and escape the tar-pit of the game. So needless to say I was very excited to hop straight into this seasons provisionals. AND GUESS WHAT I WON 7 OUT OF 10 AGAIN. Im super happy and proud of myself that I was able to achieve this and I felt I actually earned it this time! It was very satisfactory after all that struggle of climbing and falling of that low tier ladder, but imagine my surprise when after what I believed to be a very big steppingstone in my gameplay that I had pride in...landed me in Bronze 5. Not only have I never been in Bronze 5, even in my worst states of gameplay, but I realized that maybe season five was just season four repeated, that I thought I had achieved something just to end up in a worst spot then I had ever been before, and the worst state allowed in the game. Im not mad, Im just disappointed and a little bit confused, I understand that the game is using a new ranking system called MMR, Im unsure what exactly it takes into account when placing you in a tier but I feel that no matter what math is used in the MMR, a 7/10 win rate for placements shows a little more then Bronze 5. In the end I am upset after getting my hopes up and playing these past 10 games with more focus then I had ever done so before, but perhaps I am missing something that is vital to why I was ranked this way so I hope you can answer my question. Why did this happen, and what can I do to fix it?