I used to have really heavy periods that lasted quite a while. I started taking birth control so that I wouldn't have to deal with the massive blood loss and cramping each month. 20 days ago I ended up having unprotected sex, and now that my period has come around, it's very light. Instead of going through 2 or 3 maxi pads a day or 2 to 3 tampons, I've used 1 "regular" tampon each day. Today was the 3rd day. There is some blood, but there definitely isn't as much as I'm used to. Is this just the birth control pills doing their job, or do I need to worry? Also, could stress be a factor? I've had back pain, but it's most likely due to having to carry around quite a few heavy textbooks both in my arms and in a bookbag all day. Also, I postponed my period for one day for the weekend. Could that be a factor? I really don't know what to do, and I'm afraid to tell anyone.