Hi, Thanks for posting in HCM. I understand your concern. It is not practically ruled out that you cannot become pregnant if you had intercourse during the last week or so before your periods. This is because, it is difficult to predict when ovulation has occurred as it doesn t happen perfectly on 14th day of every cycle. If it happens few days late, then your fertile period shifts accordingly and also ovum is generally viable from 24 to 36 hours. In your case, since the first pregnancy test has come positive followed by another negative, it appears to be inconclusive. In such a case, you need to rule out pregnancy by getting your blood checked for beta hCG levels and trans-vaginal ultrasound scan (TVS). Kindly consult Gynecologist with report for proper evaluation and management. Hope the information provided would be helpful. All the best.