I need help!!!

Hi girls! Last week July 25th I noticed some spotting in my panty line, I thought it was going to be my AF but hours later I went to the restroom and I didn’t have no blood in my pad until now July 31st I don’t have no signs of period, I tested right now and it came out negative... what should I do? For the last couple of days I’ve been having lower back pain, headaches, nausea and fatigue. My period should’ve been here last week around the 26th... I need help