After we lost, I used to be upset and become even more of a miserable sod all weekend. Now I just say "ah well" and carry on normally. In other words I am ceasing to care and that is really worrying.
I'm finding the same thing. We had an outing to the pantomime followed by a meal with the whole extended family yesterday. I looked at the scores on my phone twice. The first time we were 2-0 down. Once upon a time that would have peed me right off and I'd have been refreshing the page every few minutes in the hope of getting a goal back. Yesterday it didn't even cause a flicker of emotion. I then forgot all about it until around 5:30 when I suddenly realised the game would have finished and checked the final score. I wasn't surprised by it and, more worryingly, wasn't bothered by it either.