My first day of menstruations was last Sept 4, 2009 and it ended at Sept 8, 2009. I had engaged on sex after which was Sept 9, 2009. Last July 18, 2009 I had brownish menstruation like until Sept 19, 2009. The hospital made a urinalysis Sept 18, 2009 and it showed Negative is it accurate? I have a regular menstrual cycle. Thanks./