Rank Placing? New Season.

OK...so I'm sad...and very angry that all last season I was in bronze 3 for the longest time. At the end of the season I made it to bronze 2 (yay finally!). New season starts; I thought I could make it at least b1 or silver 5 AT LEAST. I won 8 out of 10 games. I carried hard and I was working really hard with my team to get those wins.** ONLY TO BE PLACED BACK IN BRONZE 2..THE SAME SPOT WHEN I STARTED**. Whats with the ranking systems? I personally think 8 out of 10 is great, why did I still end up in bronze? I'm not sure how the ranking system works so someone please enlighten me because right now I think the system is kinda harsh and doesn't make any sense to me