Glow said AF should have been here on the 8th. I tested on the 9th and got a BFN. Then glow pushed my AF to the 10th, when there was no sign it then it pushed it to the 12th, I also tested yesterday and today both BFN. Glow has never let me down before and always got my due dates bang on so I'm really confused. If I'm not on my period and I'm not pregnant, what else could it be?