Hey there. Well, we can be late for a variety of reasons that might seem like no reason at all. They include being stressed, upset, sick, changes in routine, weight gain or loss. We don't really skip periods, we more have a longer cycle for that particular month. When that happens, we have ovulated later than what we thought. Then our period comes later. Pregnancy tests are pretty accurate and are considered conclusive at 2.5 weeks after the sexual encounter.
Are you trying to conceive?
If your period is overdue and you have tested properly, the home pregnancy test should be reliable by now. Only testing too early or testing with too diluted urine would be a problem for a home test by the time the period is due.
Your period being AWOL could be caused by stress, or sometimes a woman just doesn't ovulate in a given month and skips a period.
If nothing happens by tomorrow or the next day, test again with first-morning urine.