Negative 2 days before AF due

I took two tests today (first response early detection and clear blue rapid response) and both were negative. I believe my period is due in 2 days. I have symptoms that are not usual PMS symptoms for me. My nipples are very sore and I’m exhausted. I never have sore or tender breasts before my period. Is there hope that I am pregnant? Maybe HCG levels still too low to detect? Anyone else still got negative tests this close to AF due date and been pregnant?