help! Evening primrose oil &ewcm

kelly
Been ttc for 18mths my local pharmacy suggested taking evening primrose from cd1 to ovulation. only problem is i've had ewcm and lots of if since cd5 til now cd8 i've been doing ovulation test but all negative. is this normal for taking evening primrose oil? How will i no when i'm gonna ovulate if this continues? Any1 have any experiences with this please help.....