This is my 4th cycle of ttc. During this time I've had 3 42 days cycles (which is normal for me) and my last cycle was 37 days. The <a href="https://play.google.com/store/apps/details?id=com.glow.android">glow app</a> says I should have started on the 20th Aug (42 day cycle). Still no af and tested negative today. Feeling deflated, how long should I wait to test again? I don't feel as though Af is coming and I usually get symptoms. I've had a headache and nausea on and off for over a week. I'm hoping I'm still in with a chance. Lots of luck to you all.