I am 20 years old and my periods has been delayed by 12 days already but I have not got periods yet. I feel slight cramping and pain in my lower abdomen and waist similar to pre menstrual cramps. I am not sexually active so pregnancy is definitely ruled out. Normally I get regular periods with a good flow. Please suggest some tips aur medicines to start my flow as soon as possible as this tension is affecting my studies and daily life. Please help as soon as possible.