Are Hearing Tests How Accurate?

I just had a hearing test 18 months after my last two hearings tests around January 2019. Both audios performed in January 2019 were similar. The one I had done today was completely different showing massive changes for the worse. Where I could hear in the ultra high frequencies between 0 and 25 dB, today I couldn't even hear past 8 kHz. My values at 8 kHz changed from about 10 dB to 40 dB.

With COVID-19 the headphones they put on me where over the ear and had this plastic covering around them. The ones I used before were like shooting range head phones where they engulfed the entire ear. I swear it made hearing the sounds so much harder, or maybe my hearing is just super bad suddenly. The plastic on the outside also magnified my heart beat.

Is it possible this hearing test was inaccurate? Has this ever happened to anyone before where they test really bad then have a test again and everything is fine?