My cycles have always been regular, with my periods lasting around 3 to 4 days. Some cramps, but nothing severe. Bleeding isn't too light or too heavy. But this month, I started on the 2nd and it's the 17th and I'm still bleeding very lightly. The entire period has been very light. Like if I change my tampon every 4 hours there may be nothing on it, or just a couple of faint spots. I'm not on birth control, and there is no possibility of being pregnant. I've never experienced this kind of period before.