False OPK

Help, anyone! Has anyone had false opk during cycle when taking clomid? Last month I took clomid and received high and peak fertility and then a week later started having lots of EWCM and decided to do another opk which was peak fertility again. Why is this happening? My cycle length with the clomid was 39 days, which is the longest I've ever had. It's like the clomid pushed back my ovulation. But according to the opk I was going to "ovulate" and then going to "ovulate" a week later.