Hello I'm 19 years I have sex with my boyfriend when I finish my period I really don't remember when it was I think it was on October 3, 2012 and we had sex first without protection he didn't but it was a quickley then we had with protection and it passed like to days after then it came out from my vagina a brown discharge for like 6 days then it stopped and the thing is that today is October 28, 2012 & I miss my period & idont when it supposed to come & I'm scared

Better you go to doctor and see.
Or
Test your pregnancy with the help of pregnancy test meter.

Take a home pregnancy test with your first morning urine.