Still a chance of pregnancy?

According to glow, I was supposed to start my period today, but so far nothing except for some dull cramps in my lower right abdomen. I was experiencing some symptoms of cramping (some like ovulation, some like menstrual) during 2ww. I took a FRER on Saturday around noon, which would have been 3 days before expected missed period (said 99% accurate within 3 days of period) and got a BFN. Unfortunately I haven’t been great at tracking on my app so it could be a little off, although I did track my period accurately last month. Is there a chance I could still be pregnant? If so, when should I test again?