I am 19 years old and i've had my first period when I was 13. My periods were normal till I was 18 but a month before I was about to turn 18 the most horrible periods happened to me. First and second day were normal with less pain and normal flow, but on the third day there was no flow but agonizing cramps. I was vomiting, crying and it was hurting like hell. This pain wasn't like the normal cramps which I have during heavy flow. In fact there was no blood coming out. the pain lasted for 3 hours. After that everything was fine. After 6 months the same thing happened to me. And now it happened to me yesterday which was the most painful 3rd period day. I didn't know what to do. I couldn't eat anything because nothing stayed in my tummy not even water. I puked 5 times which was just water (because I didn't eat anything). After 3-4 hours I was fine. But I don't know what am I supposed to do if this happens to me again. What is the reason behind scanty flow and so much of pain on the third day of my period ?