Does anyone struggle with OPK’s? I drink typically 6-8 bottles per day and this month I’m really struggling with my ovulation tests. I had a dark almost positive on CD13 and then faded off after that. Should I assume that was my surge? I’ve been cramping which usually happens after I ovulate. I’m CD16 and have tested twice a day since and all -. I have regular 29 day cycles. Tia!!