Hi there!
I just started using it this past month, so I am still learning it myself! I seemed to have the opposite problem, I had a ton of High fertility days, and I am pretty sure I didn't really have high fertility on all the days that it said I did!
But I think it does take at least one month of using it for it to "learn" your cycle and give a more accurate and pinpointed result of ovulation. Hope that helps!
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"Let us not become weary in doing good, for at the proper time we will reap a harvest if we do not give up." - Galatians 6:9

TTC on our own for over 2 years
Dx with Severe MFI- Blood work shows no Microdeletion and no CF mutations
Ultrasound scheduled 3/22- DONE! Everything looks normal, other than some cysts on my right ovary.
HSG scheduled 4/14- DONE! Tubes are clear!!

On BCP until our IVF w/ICSI scheduled for August!!!