Can a High fertility Smiley X3 days on Clearblue Digital Monitor Mean you're pregnant

Af due in 4 days but I'm always late. I tested 3 times and have gotten a BFN however the CBDM shows I am 3 days high fertility. Is it possible that HCG levels are too low? I'm not sure exactly when I ovulated but he been enjoying tons of baby dancing with the hubby. Thanks for any advice:)