Light Brown Discharge & Potential Pregnancy: What to Do?

Question
My last period was May 9 with my average cycle being 33 days.  My husband and I are trying to conceive and I have been trying to monitor my cycle.  I am now 3 days late for my period, but I have had very scant brown discharge only when I use the bathroom and wipe for several days---though some days nothing.  I have not needed any pads or liners at all.  I took an HPT with first morning urine on June 12 and got a negative result.  Should I retest, or is this possibly a period?  I am usually quite heavy for at least 2 to 3 days.  

Answer
If you have a 33 day cycle, and your last period started on May 9, then you were due for your following period on June 10. The best time to take a pregnancy test is seven days after missing  your next period. Therefore, the best time to take a pregnacy test is on June 17, not before. After that,a pregnancy test will ber accurate.