Late period still negative

AF was supposed to start Monday. Still no sign. I’ve been cramping but no spotting or anything...YET. Last time I took a test was Monday night and it was negative. Of course since I put in Glow that my period didn’t start Sunday it bumped it up two days which would be today, yet still nothing. Should I wait until next week to test? I am so sick. So so so sooooo nauseas. I’m at school (college) and I’m about to go home because I’m so sick.