OK so I'm usually regular with my periods 28-30 days. Last month my period started July 3 - 7th with reg flow. My husband and I TTC 4 days during ovulation. This month on CD 33 I had very little brown spotting for 4 days ( very little quarter size). Each day for the 4 days it was less and less. Not something I would say was my average period. Tested a few days ago with a Walmart cheap .88 cent one and was negative. Could I be pregnant???