Confused opk! Clearblue digital vs cheapie

Gabrielle

Clearblue digital advance tests have been flashing smiley face (high) for 3 days no peak. The cheap line opk were clearly negative until 3 days ago when I got a very clear positive cheapie. Why is clearblue only high fertility and clearblue is very positive for two days ? Which should I believe? Also ewcm has been for a week, a little less today.