my cycle is usually 26-28 days. I had sex on the ninth day of my cycle, which on <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> it says I was ovualting but I've used a ovaltion calculator and I shouldn't have been ovualting yet. I was due to start my period yesterday, but I haven't yet which has become the norm (being a day late). I haven't taken a plan B pill and I'm not having any pregnancy symptoms. should I worry?