So I've been using Glow for several months now. I previously used <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Period Tracker</a> for 6 months. My husband and I have been TTC for 9 months now. Glow is normally spot on with my periods being on time. Since I've been using this app I've had a couple months to where I start my period anywhere between 2-4 days before Glow says I'm supposed to start. And we typically try to have sex more often during my fertile time. When I start my period date on my calendar it automatically changes my fertile week from month before. I guess my question is when it does that does it mean that we had sex on the wrong days during my "green week"?