Very confused!

Hello ladies. I don’t know if someone will have any kind of answers or ideas but I’m going to just shoot. I have a very regular cycle... and have had ever since I started my period, even after a child and being on and off birth control. My cycle came right back as normal and like clockwork! We’ve been TTC for two cycles now and I am five days past a missed period. I’ve never had that happen except when I was pregnant with my first child. I’ve taken a few pregnancy tests over the course of the past six days since I was supposed to start. They are ALL negative. One of the tests didn’t even seem to work right. I have no idea why I’ve missed my period and all other explanations I can find do not fit. I think I need to make a Dr appt, and I also would like some feedback from any of you ladies who have experienced the same thing.