Hi, it's always better to test once your period is late with your first morning urine. It can show as negative few days before period and then positive later on when you're late if you're indeed pregnant as it picks up HCG in the urine. Period tracker is not 100% accurate, but you can roughly use it as a guideline like what I did. Sometimes due to stress or various reasons, we might ovulate late or not at all that month. From what I know, we all have a 20% chance every month of falling pregnant even if you did it during your fertile period.
I was like you, seeing negative after negative and getting sick and tired of my period coming month after month and wanted to give up and take a break. I fell pregnant on that month I didn't expect anything, life surprises you in mysterious ways. Just keep yourself occupied, do your fav things and enjoy your life. Your positive will come soon!! 🥰🥰