when to take a test

Brittany
So me & my husband had unprotected sex on April 18th which was my peak in my fertile week is what Glow says. The very next day that evening I had egg white CM, this week I've been having cramps, nausea, headache today. We are praying that u become pregnant. My next period is suppose to come May 3rd when should I take a preganancy test? 
Thank you ❤️