Does Missed Periods After Protected Sex Mean Pregnancy ?

Hi, may I answer your health queries right now ? Please type your query here...I was suppose to start me period on the 8th of this month and i have not yet. i had have sexual intercourse with one individual with no protection who I was dating. and started my period on the 8th of last month and we did not have sexual intercourse after. then the end of last month I had sex with another individual and we used protection and i have not started my period this month and is now extremly worried.