Hallow Madam,
The very fact that you had bleeding at the time of your expected menses indicates that the chances of
pregnancy are very low.
You had intercourse around the day of egg release. Your calculations are absolutely right. So the chances of pregnancy have to be kept in mind. Thus another possibility that remains is you were pregnant and aborted completely; hence heavy bleeding followed by brown bleeding and then no bleeding.
The best way to resolve this dilemma is get the
ultrasonography done. Urine pregnancy test will not give you any useful information after this incidence. If the pregnancy has been completely aborted, it will not be seen in the
uterus. If it is incompletely expelled out, it is reflected in ultrasonography. In that case, you will have to get it removed by surgical intervention.
If there no products are visualized in the uterus, may be due to complete
abortion or due to no pregnancy, it should not make any difference for you.
To avoid such
stress in future, it is advisable to adapt some reliable birth control method like
intrauterine device, birth control pills or condom. Now a days, female condoms also are available.
I hope your query has been resolved satisfactorily.