How accurate is Glow? Please read and advise me

Emma • Baby #1 - Boy 💙 born 14 July 2015!!
I have been TTC with my first for 5 months now and have used Glow for nearly 2 months. It told me that today was my high fertility day with tomorrow being the highest so I was really excited about the days ahead. Only trouble is I took an ovulation test (clear blue digital) this morning and it showed I was in the 'low fertility' stage?? So I'm feeling disheartened. I logged this on Glow and now it says I'm most fertile in 3 days time?? Just a little confused and suppose just expected this app to be pretty accurate. Please can I can some words of encouragement from all you mummy's to be. Baby dust to all xx