Need some help...

I had unprotected sex around the time of my fertile window. My period is 5 days late. I've had cramps and a few signs of my period, but not nearly as many as usual. I took a pregnancy test from the dollar store two days ago and it said I'm not pregnant but I've heard they're unreliable especially because I didn't use it first thing in the morning. Am I pregnant? Buying another test doesn't look like an option because I'm trying to hide it from my parents.