Help! Strange AirTag Found Traveling With Us – What Should I Do?

I recently attended a concert with my partner and brother, and on our way back, my brother received a notification about an unknown AirTag that was traveling with us. We located the AirTag using sound and discovered it was in our car, next to the oil tank. The only people who have access to my car are my parents, and I'm concerned they might be tracking me without my consent. Although both my brother and partner received notifications from their iPhones, I did not. I've checked my location services and looked for unknown apps, plus tried to use the 'found unknown device' feature on my iPhone by placing it on the AirTag, but it didn't recognize it. I feel really anxious about my safety and am considering taking my phone and the AirTag to the Apple Store to figure out why I wasn't notified. I want to disable this AirTag, but I'm worried there could be others that I won't be aware of.