Late but two negative tests help?

Hey ladies so here I am 7 days late af always comes every. 28 days no symptoms of it coming nothing. I should have started the 31 st but instead had cramping that I thought was ovulation. But then no period I never ovulate this late in a cycle but also never have Late af. I've tested 2 Times once on the 1st and then yesterday morning both neg. could the cramping on the  31st been implantation? And it's just too soon to see results . Going to wait a week I think. Before calling the doctors