hello, i am 15 years old and i have had my period for 4 years, i've missed maybe 2 months in total out of those years. the last time i've had my period was Dec 15 2010 and it lasted until Dec 21 2010 i was not stressed out or worried about my period in january but i missed january. i will admit i have masterbated alot during january, but i doubt that has to do with my period. im irregular and my periods come when it wants to...but im getting worried, btw i am not sexually active, i am a virgin. can you give me an explanation as to why i mised it?