I have been taking ortho-trycycline for about 6 months. I am getting breakthrough bleeding for the first time and it has lasted 4 days has has been enough to stain the toilet water. Im freaking out that I may be pregnant or it may be a complication with my possible hpv. (i have a copo appointment soon). I realize some breakthrough bleedin is normal, but I need your opinion. Im sexually active and quit smoking. As a student im a little stressed but not enough to effect my health. Help!!!