How can I find my lost AirPod?

I was in school listening to music with one AirPod in. Then when I was leaving I got a notification on my phone that one of my AirPods was missing so I returned to my school to try and find it but I tried for an hour and was at the exact location even going around in my school looking for it while trying to connect to the sound in find My. Nothing worked and my school was closing (which is a tall building if that helps) so I had to leave. While I was leaving with the find my still on it said that I had it on me (following me not in the case) so I took of my jacket and checked everywhere and it still wasn’t there and my train was coming. I hopped on the train and then it stopped following me. It still says that it is at the station that I checked multiple times and didn’t find it or get a connection. What can I do to find it? I have felt really bad losing a gift I got from my mother.

[Re-Titled by Moderator]