Advice needed!!

Keyra
Fiancé and I have decided to try and conceive. I had my implant removed from my arm four months ago. These are my last two periods but <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> is saying today I should start.
My other app says it won't be until next week. We had sexual relations all during my period and the day after it ended. Was wondering if anyone else has had a misread of when period is expected or should I think maybe I took this month?