I have a regular 28 day cycle because I am on the pill (estrostep). I was due to have my period the week of 3/26-4/1. I had sex on 3/19 while on the pill, but I took the pill late by a hour or two the next day. When I was supposed to have my period I had a day of what looked like a normal period (red blood), but followed by a 4 days of spotting (brown discharge). I also spotted during hte week of 4/10. Could this be implantation bleeding? Or is this a side effect of the pill? Ive been on the pill for 6 months now, and this has never happened before.