Period 7 days late but multiple negative pregnancy test

Hi guys, I’m really concerned, my period is now 7 days late but I have taken multiple pregnancy tests and they have all been negative. We have been TTC for 7 months already and nothing, since we both just turned 40 our doctor suggested to use Clomid and see what happens. We just did the Clomid for this past cycle and my period should have arrived 7 days ago. I don’t feel any of the early pregnancy symptoms so not sure what to think. I did a betaHCG also after 2 days my period was late and that came back negative as well. I am waiting until next week so I can repeat the betaHCG, getting nervous 😬