is Predictor Early a reliable test?

Hi ladies. Here’s my question. I had unprotected sex with my SO 2-3 days before my period and now my period is 10-11 days late. I’ve used Predictor Early a few minutes ago and it was negative. Plus I feel nothing, I don’t have nausea or anything. No breast sore no headache. Just little cramps on my ovaries. I think I am stressed out and this caused a delay on my circle. On the other hand, I have really irregular period circle.. soo, I am confused 😅 can I trust this test? Should I take another one after 3-4 days?