Wow- I’m in the same boat girl! I’m on day 4 with no aunt flow, so I totally understand how you feel. I’m always regular, and have been trying with my fiance for a while now.
If you can get to the doctor, do that first, since most home pregnancy tests are sensative enough to pick up early pregnancies (some are, but most aren’t)
Blood tests work best in early pregancy detection.
If you can’t get to the DR., try getting a home test that can be taken as early as the first day of your missed period. That may work.
Good luck to you girl 🙂