Hello, Welcome to health care magic. I have read your question completely and understand your concerns. I understand that you are on contraceptive pills. So when you say you ran out of birth control pills does it mean that you finished this month pills and then are on the pill free break of 7 days, hence you are due to see a period this week? Or you are on the pills but stopped them mid cycle?? If the first scenario is correct that you completed this months pills and you are on the pill free break, it it is unlikely that you would be pregnant ( provided that you did not miss any pills in between.) If the second scenario is correct that you ran out of pills mid cycle then, still it is too early to say whether you are pregnant now. You ran out of pills on Saturday and on Sunday you had sexual intercourse. On Monday you started bleeding which was light- this is unlikely to be implantation bleed as implantation bleed normally happens 1 week after fertilisation /fusion of egg with sperm. You could still be technically pregnant as you missed your pills, but you could only confirm this after about 2 weeks. I feel it could be your period( normal withdrawal bleed as result of your contraceptive pill) . In a woman who has regular normal periods, it is not unusual to have 1-2 light or heavy periods or 1-2 early or late periods. If persistently your periods are irregular and different ( light or heavy) or if you start spotting in eternal your periods, then you need consult your doctor. I hope this answer has helped you. Thank you Regards Dr Sunita Sayammagaru