Hi there and welcome. Periods can be late for a variety of reasons. Generally, pregnancy tests if taken at or after the time your period was due are very accurate. Being late for a period happens to most women at some point and not because of pregnancy. I'd trust the tests at this point.
(not to mention, nausea starts on average for most women at week 6 to 7 for most women).
So, things that affect our period are stress, changes in routine, weight gain or loss, illness and sometimes nothing at all.
I'd wait a week. If your period still hasn't shown, then take another test. If it is still negative and you are worried about pregnancy, see your doctor. They 'may' do a blood test on you. Once in a while the home tests are wrong but usually that isn't the case. But you could be one of the rare cases.
good luck hon
It could be stress. Intense stress can mimic pregnancy symptoms especially if you're preoccupied with possibly being pregnant.
How early after a missed period did take the test? Is your period late? Without a timeline, it's difficult to find any possible problems with the test.