I fooled around with a guy for the first time about a month ago. No intercourse...but, oral. About 2-3 weeks later I developed an itchy rash on my vulva which worked its way to my vagina. I treated this as a yeast infection. The rash on my vulva has come back and on top of that I have missed my period! I know many factors can cause a period to be late/missed. Any thoughts/advice on why my period is late?...Could it be an STD? Stress?