BBT high day af due ?

Natalie

My bbt is still high and af due today . I have boob pain that feels almost bruised to the touch , congestion randomly , fatigue and keep burping 😂 . Could this be a good sign? Had a period feeling cramp yesterday lasted 2 mins then stopped , maybe implantation? Is it normal for bbt to be high day of period , as I thought it was meant to go down?