I believe the time period has changed, and is dependent. The main question is whether or not your are vaccinated. If you're not, get vaccinated as soon as it's okay to do that. At this point in the pandemic at least in the US, the chances of being exposed to covid at the doctor's office isn't high. Most places don't necessarily see covid patients, there are specialized places for that, and you generally have to wear a mask and distance is maintained. But the best way to get out of this is to get vaccinated if you're not already, it might not keep you from getting covid but it will almost certainly keep you from having a bad case of it.
Why are you testing, did you get exposed to someone with Covid? If so, how long ago was it? If your test was a couple of weeks after your exposure to the person and it was negative, unless you continue to have exposure you can probably go on with your life (put on your mask and go about your normal routine). But if you think you've been exposed anew, then you should test again.