I am an avid runner, i have always had a light period with a cycle of 30-35 days, lasting about 3 days. Yet lately it has been decreasing, and seems to have stopped. I have recently been increasing my running to 4-5 days, between and hour to an hour and half of running. I thought if i could increase my weight it would come back (thought it might be low body fat), but i have gained from 50kg to 52kg and still nothing (though i do not know if it was from eating or muscle gain). i need to know if there is a chance it might come back, and my body is just adjusting to the increased running? and also why it might have stopped?