My periods were due on May 7th, but they haven't started yet. I experienced nausea on the night of May 6th while eating out at a restaurant. I'm not sure if it's a sign of pregnancy, hence the doubt. I'm sexually active but we always use contraception. I have been having anxiety attacks ever since that episode of nausea. I also took a home pregnancy test on the morning of 7th May, but the result was invalid. I'm confused what to do now, because my periods are usually very regular despite having PCOD. Kindly help me with this.