My husband and I are trying to have a baby. We had sex about every other day during my fertile time. My period is not due to arrive until Saturday the 13. I started having cramps and some brownish spotting today. It's only noticeable when I wipe. I also took a hpt last night, but it was negative. Am I pregnant or am I starting early?

You could be starting early. Take the test again using first morning urine as it is more accurate than taking it any other time of the day.