Unless you made a mistake and didn’t follow the test instructions correctly, don’t take multiple tests on the same day, or the next. The results will be the same.
If your pregnancy test is positive, there is little value in taking additional tests in the hope they will be negative. Instead, make an appointment with a medical practitioner and discuss what happens next.
If your result is negative, wait a week before taking another test. This is especially true if you take the first test before the day your period is due. At this stage, there’s still a good chance these tests will provide a false negative.
If you can’t wait that long — and I’ve been there — do wait at the very least two days, preferably four. On average your hCG levels double every two days, so even waiting one day is unlikely to change the result.
If you continue to get negative results and you are still late, visit a doctor as there are many other medical reasons why your period can be late.