Hello doctor, During a few cycles i am having severe cramps before periods till the flow starts. It never happened earlier. My periods are quite regular just once it happened that I have a 45 day cycle but nothing after that..usually the cycle is 29-33 days. The pain and cramps are so severe that it makes me dizzy, my legs numb, nauseous and I can't get up or walk or do anything. It starts with very light bleeding and then normal flow and stays for 4-5 days. I am really not getting such severe cramps. Never happened earlier.