I heard sickness and medicine can throw off your cycle/period. The week before my period I was pretty sick. Really sore throat (might have been strep throat) I was taking Advil, Chloraseptic,and Cepacol. I also wasn't sleeping properly, or eating too properly. I had this sickness the week before my period. My period which normally lasts 5 days, only lasted 3 and it was ridiculousy lighter than normal. Could this be caused from being sick/medicine etc.? Or what else could this possibly be?