Late period not pregnant

So my period is over a week late now. I took a pregnancy text today and it came back as negative. No faint line, strong negative. What could be causing this? I’ve had white discharge for the past week. No cramps, have bad acne no, boob is hard, all my normal pms minus bloating. What could cause this to be late? I’ve never been this late before - I’m 20 not on birthcontrol. I’m waiting for my period to come so I can start a new one when it ends.