So i am not sure when i ovulated, i have irregular periods and it took me three years to conceive my daughter since i have PCOS. so i think i ovulated anytime between the 21st july and 24july, about a week after i started getting period like cramps that went away if im right i should get my period again on the 9th of august but now for the last couple of days i have been having diarrhea about three loose stools a day, no other symptoms except occasional nausea, ive been testing for pregnancy for about a week and all negative could this mean i have conceived but still too low hcg to be detected.. any opinions or advice.

im now two days before my expected period