My period was due the 3rd or 4th of this june.. (as it came at the same time last month) ..I had sex the day right after my period (May 10th) .. when june 9th came I had some dark brown spotting in my underwear...it is now june 27th .. my birthdays tomarrow and im turning 18..my nipples get hard/sore like they always do before I get my period but it wont come.. maybe because I was stressed last month? ... Help.