How Can Amenorrhea Be Treated?

hi,i have been experiencing irregular periods and i am scared.sometimes i don’t have my period for up to six months,sometimes it could be less or more! a few years back it was always regular at least every 8 weeks but for about 3years now it stopped being regular..the last time i saw my period was about 6months ago..what does this mean?is this a sign of infertility?i am still a virgin and i have not used any kind of contraceptive .i am 26 years old