EXTREMELY CONFUSED AND SLIGHTLY WORRIED

Amanda
Okay so today is April 20 and i just logged my BBT for glow. I always log everything that meeds to be logged and according to the calender, my fertile window was from April 9 to April 16. I had sex on April 18 since my fertile window had ended and since April 16 glow has been giving me the little "3% risk of pregnancy" so i thought i was fine. Now I'm looking at the calender after i logged and it says my fertile window completely shifted! It now says my fertile window was from April 14 to April 20 and that April 18 was my high risk day of 33%. I'm just wondering why glow would change like this and if this might have been a glitch or just why it took so long to adjust. All we did was pull out which isn't the best way to handle it I know but can someone give me some answers??