Hey ladies my last period was on June 1st. And for the past 3 months my period has been on time at 26 day cycle. I got a positive opk on the 16th and was very crampy. I was supposed to start my period on the 27th. Well it hasn't came yet. So I have tested using first response and they have all came back negative. We have also been trying to conceive. Anyone have any idea what could be going on?