ok so last time i had sex was in June. on oct 24 i went on vacation and i had sex 2 days ib a row with condom (i am not on the pill) my period wasnt due for another week yet i got it 2days fater the last day u had sex. example. 10/24 sex 10/25 sex and got period on the 10/28. . first i had brown discharge then normal period for 4 days .... QUESTION IS.... WHY DID MY PERIOD COME EARLY ?? should i be worried