In the current situation, with incidence going through the roof, a negative test does not say anything, and a repeated testing after some time just checks if a probable infection has become infectious.
That said, in this situation, with incidence going through the roof, a positive antigene test should be considered positive. Advice: ISOLATE yourself immediately. Do not wait for a PCR test. In fact, if you can avoid it, don’t get one. Leave the PCR testing capacity for the clinicians, the frontline nurses, and everyone who has to take the risk of infecting other people while being asymptomatic.
OTH, if you get symptoms, without testing positive with a rapid assessment test, assume that you have COVID-19 until you have a PCR result stating that you are not infected.
That, too, means that you should isolate yourself to the best or your ability. Stay away from others, wear a FFP2/KN95 mask correctly, wash your hands frequently according to the guidelines, and control yourself by repeatedly testing with rapid assessment tests like I described above.
If we can’t really beat the virus, we can at least and literally buy the people in the healthcare sector some leeway.
I, for one, am going to test myself in about 8 hours from now. And I went for a nasopharyngeal RAT in a testing facility this morning - if you are vaccinated, you’ve got one for free, paid by the city, per week.