Hi Doctor, My Name Is Suchetha.I Have Certain Concerns Regarding

Hi doctor,
My name is Suchetha.I have certain concerns regarding pregnancy and menstruation.Actually my period is regular. My last period was on November 26. and on December 28 I had a brownish and pinkish spotting and from December 16 onwards I have frequent urination also, but it stopped from 9 December onwards.
Yesterday I had periods and its really a normal period.Could you please tell me What will be the cause of it?

Added background Information..

I have been consuming folic acid for 1 month and me and my husband had an unprotected sex also.
Our marriage was held 2 years before and we were trying for the pas 6-7 months. I had checked my uterus and hormones it seems normal and my husband has 35% motility and consumed tablets of F-Hood we had an unprotected sex for a week from December 9-16.