early period?!

Noell • Single!
I'm so confused!! I had sex a week and a half ago, without protection so I took the day after pill. 
2 days ago I had sex with protection. 
The next day I started bleeding. I usually bleed after sex because I am super sensitive, but this time it was a weird brown blood, no odor. Then I'm full on bleeding today and I have period symptoms, but I'm not supposed to get my period for another 12 days! Is this normal??