Please help me, and can you relate?

I am now 6 days late on my period, I keep taking pregnancy tests but they are coming out negative. I thought I was actually getting my period yesterday because I had cramping but nothing I’m just having discharge...not exactly sure what that means? Has this happened to you before? I am extremely tired lately, frequent headaches, nausea, hungry..so I can’t tell the difference between pregnant or period. When should I retest?