I have a query that I want to get resolved. It's about the person i'm in a relationship with. Actually it's related to her period. Prior to last month she had a 45 day cycle and and the menstruation started on the 1st of april and got over around 4th of april. We had sex on the 6th of april just two days after the period got over. I did insert just once without any protection without simulating and whether it and just after withdrawal I saw a tiny drop oozing out just like precum. I didn't release anything as there was no stimulation and no orgasm after that we did use the protection while doing it and and just to be safe she also did take the emergency contraception pill. She did experience spotting after 5 days but after that it was all fine. We did checked for pregnancy and did 3 tests on days 1st 6th and the 13th all in the month of may the latest one 38 days after having sex and all came back negative and she too is feeling no change in her body but her cycle is 1 day late now. What can be the reason for this? Is there a cause for concern?