Cramping, nauseous, implantation dip?

Alyssa

My period is due tomorrow-Friday (depending on the app). I have been cramping the past couple of days and feel shaky and nauseous today.

Could CD 37 be a possible implantation dip?

I thought I was on the downward spiral to Aunt Flo. Then I had that high temp today.

Tested today and a BFN.

Thoughts?