I am sitting here all alone thinking 'Why don't the holidays excite me anymore?'

It's a really sad thing, bailey, all the more because this is a burning reality of life which shall happen to all of us at one point of time or another. As you grow older, you'll have gone through so many holidays and so many fireworks displays that you will no longer feel excited at them. Neither does it mean that what you're doing staying behind will be giving any sort of pleasure. Even if your mind is willing, your body doesn't agree. This conflict itself makes you more fatigued and the desire vanishes. Also, the adrenaline secretion has lessened in your body which tends to make you more inactive. I'll suggest one thing: force yourself to go out with your family. Don't think whether you'll like the experience or not. Isolation is more of a burden, in my opinion. Try to think that you're enjoying the time. Our mind often works as a catalyst. If you think positively, a positive outcome will transpire. Do try it. Cheers.