i recently finished my placement games and wow im confused i went 7 wins and 3 losses yet i am in bronze three. wtf?????? i feel like riot didnt care about my wins or losses. i am actually lower than BEFORE i was in silver and now im in BRONZE??????? someone please explain the knowledge*[zombie-brand-mindblown]* 
People have already talked about this. You get a "soft reset" which means your mmr goes down. It is normal for this to happen. (challengers get into plat, Plat into silver, Gold into bronze etc.)
There is a fairly good thread that explains this: http://boards.na.leagueoflegends.com/en/c/gameplay-balance/E9nkYATc-psa-regarding-ranked-placement-and-seedings-for-all-who-are-confused
