Hmmm... I'm hoping and assuming you have never contracted an STD. Now one of my friends just doesn't have her period regularly. It could
be something like that... Or...
It looks like if you are underweight, then your body cannot support ovulation and therefore, you don't have your period. I would suggest gaining more weight and keep it on
. If you gain weight, then wait a week, and give up on it and lose that weight, your body will not take to it. Give it some time. Try to gain up to 120 at the very least, but if it still doesn't show, then try keeping that weight and simply drink more fluids (they have magical powers
Hope that helps!