I have done sex with my gf on 2 oct and that is the starting of their periods and then I do agin sex on 17 oct and then see got theirs period on 24 oct and in 2 nov I do sex again and I give the unwanted 72 and she get a withdrawal bleeding on 10 nov but today is 18 dex she didn't get periods. She also take the home pregnancy test and it is negative and also do the beta hcg test and their level is 0.100.is their any chance of pregnancy or not. please confirm sir.