What is this and why

Kim

I’m currently around six days late never ever been late before cycles are like clockwork. Done a pregnancy test Tuesday blood work was negative but she said if I ovulated late then might not be enough of the hormone in my body. Just for the fun of it took an opk today why is it as dark as this I mean I know I’m not ovulating I understand it isn’t dark dark but right up to cycle day 20 it was barely there. So confused as to what’s going on never late for my period only once and I was pregnant with my daughter .bottom test is today th one in top is yesterday