Hi I'm 18 years old. My last period was on July 21, 2007. Since then I haven't gotten it, but I took a pregnancy test and it came out negative. Could I still be pregnant or is something else wrong. I am really worried, please help.

I have not had my period in almost a year. I was always not regular, and it could be due to my diet. Recently, I had a prescription of birth control filled and they tell me to take it the Sunday after I have my period. But, since I don't get my period would I be able to start taking it now anyway?

I am 14-years-old and not sexually active. I have had my period for about 1 1/2 years now and to this point it has always been regular until now. I am 5 days late, and I don't know why. Should I be concerned?