Hi and welcome to the site.
Yes it's possible that the tests were taken too early. Usually tests would turn positive by now. But it's possible to get false negative readings if a woman has taken the test later in the day after she has already been drinking a lot of fluids. The pregnancy
hormone levels are highest in the urine first thing in the morning. This is because most women are not drinking fluid at night so the urine gets concentrated. So repeating the test first thing in the morning would be most accurate. Urine pregnancy tests
will turn positive by the time the period is due using first morning urine. If the test is still negative, it should be repeated a few days later. If still negative, there may be a different cause for the symptoms.