Go Giants, I guess?

This will only make sense if I tell you that insofar as I followed major league baseball at all when I was a kid, I was a Cubs fan. I grew up close enough to Chicago that many people I knew were Cubs fans. I've been to more White Sox games than Cubs games - but I dislike the American League, so that rules out a White Sox fandom.
Except that here's the thing: I moved away, and I started watching the occasional Giants game. I was happy when they won their World Series, and my favorite current baseball players are - or were - Giants.
So when the Giants played the Cubs at the beginning of the playoffs, I was philosophical at first, reasoning that one of my two favorite MLB teams would win. But then when the Cubs won a game, I was dismayed - and I realized that despite everything, I'd stopped caring about the Cubs.
This is interesting to me because usually, I cheer for the National League in the World Series, no matter who's playing. But this year, my realization that I'm no longer a Cubs fan has made that impossible. So weirdly, I'm indifferent to the World Series, with brief moments of being glad when - as tonight - the Dodgers win a game.
I don't understand the switch from "mild Cubs fan" to "not a fan at all", and I crept here to write this in secret, knowing that if I put it on Facebook, no one will have any sympathy or understanding, amid all the Cubs madness there. I'll never meet any of the Cubs or any of the Dodgers, and it's likely that no one I know will, either, so this strange adherence to a chosen team is just weird to me right now.
(Though if the Giants were in the World Series, I might feel differently.)