So about a week ago this little tune popped into my head. I didn't hear the tune itself, must have just triggered a locked memory or something. I know I didn't make it up because I've whistled it to many of my friends, ALL of which said they've heard it, but NONE of them could put their finger on it!

https://voca.ro/3nmJxhHzzAh

I think it's either from a TV show when I was a kid (early 2000's) or maybe from a video game... But it could be neither, or even a totally different time period. I really don't know. Mostly hoping someone who hears it will recognize it right away, but who knows.

It's been a week & it's still stuck in my head! You guys are my last hope.

EDIT:

Thanks to the help of the wonderful subreddit, I think I found what I was looking for.

As u/Mark-JoziZA pointed out, what came to me in my head was likely Avril Lavigne's 'Complicated' at the beginning of the verse. My best guess is as I couldn't think of the rest of the song, my mind made up what would be a fitting conclusion for the melody, thus not being able to think of the original song.

HOWEVER!

I'd also like to give a special thanks to u/azwethinkweism for showing me Love of an Orchestra by Noah & the Whale, which despite being an almost perfect match to the melody, I have definitely not heard before. That said, this song really hit the spot, & while it couldn't have been the correct answer, it was a more satisfying one.

Thank you all so much for the help! I can finally rest easy.