Queen Elizabeth II has died

It's weird, I've never considered myself a "royalist" but this news has affected me quite strongly. I just burst into tears unexpectedly on hearing this news and I don't quite understand why I feel so very sad. I guess I have grown up and lived my whole life (as a Brit) seeing and hearing the Queen, singing "God save the Queen" etc, and this news made me suddenly feel very old, very nostalgic, with the sense that all things pass in time, which makes my heart ache deeply.

I feel the same. I think it’s because it really represents the end of an era. The 20th and early 21st century ushered in unprecedented improvements to quality of life in Britain but it has felt of late that that has peaked and the country is facing a serious decline: Brexit, the increasingly visible effects of climate change, the aftermath of covid, the possible break up of the union, rising costs of living, recession, possibly even war. The death of Elizabeth II coincides with the end of a long period of stability and comfort and is not only a poignant point in history itself but a marker for a transitional point in history for our country.

None of those things you mentioned are real or big problems visible at an individual level any more than the problems of previous decades. If nobody told you they'd happened, you'd be enjoying the same stability and comfort as before. Perhaps the problem is how the media presents events, not the events themselves.

Without an objective way to measure "badness", all you're doing it reflecting what the TV told you to feel.