One month ago my partner and I had sex while I was on my period. We have not again since. I have been on the pill for a long time (multiple years), and he did not wear a condom. This month, my period was one day late (never happens), and what did come was only brown spotting with a little pink (also has never happened). I start my next month's set of BC tomorrow, so I can't really expect my period to come, any more so, can I? Is there a chance of pregnancy?

Thanks.