Descovy scared efficiency

Hello everyone, I'm on descovy since 3 month now, my doctor said I don't need to be worried about HIV now, but I sleep 3 weeks ago with a guy who he is on biktarvy since 3 years ( a lot of 3 I known) I did a test 2 weeks ago and negative and I did a new test yesterday, I waiting the results now and I'm o' stress. My question is who is on descovy since a longtime now and take a risk but the results stay negative? I read a lot of things on internet about prep failure so now I'm scared.