.if you have never had sex .i fail to see how you could be pregnant. .it is extremely unlikely that you were impregnated from anything other than penetration. .is their a reason you think you are pregnant even though you have never had sexual intercourse?

It is very common for young girls to have irregular menstrual periods. Are you underweight? How much do you exercise? Are you sure you're not having sex? All these things can and will mess with your period.

my stopped menstruating for several months when i was your age cos i was kinda anorexic/bulimic. if you don't eat right it can affect your periods. stress can affect your periods too.

are you eating correctly? are you stressed out by school?

at your age i suppose it is quite normal to expect your menstrual cycle to be irregular anyway. but perhaps it is safe to ask a doctor.

get to the doctor don't just worry and sit there. duh.