SearchResearch Challenge (1/17/18): How do I find this song that's become an earworm?

I was bicycling home when it happened... 

I wasn't thinking about anything in particular, I was just out for a ride. But somewhere along the way I got a terrible earworm--you know, one of those catchy songs that gets stuck in your head, and won't stop--it just keeps repeating over and over in your head. 

For whatever reason, I could NOT figure out what it was.  I could sing it, I could whistle it, I could even play it on the piano, but I was utterly unable to put a label onto it.

Of course, this immediately activated my SearchResearch instinct--how can I figure this one out?  

Here's a recording of me whistling the tune: 

           playable m4a file of the mysterious tune 

This is this week's SRS Challenge! 

1.  What's the name of this song?  

2.  If you can't recognize it... how on Earth would you search for this tune? 

Naturally, please let us know how you figured out the name.  If you just know it off the top of your head, that's fine, but tell us that.  If, like me, you know the song, tell us WHAT you did to figure this one out.  

This is an Open Internet quiz.  You may use whatever method works.  (Just tell us your secret.)  

Just so you'll know, I figured it out (using my SRS skills).  Took me about 10 minutes.  How long will it take you?  

The good news is that once I'd given the earworm a name, it went away.  I have my sanity back.  Thank heavens.  

Search on!