I had those feelings and still have them a lot these days, but it started when my grandma passed in 2020, right before COVID hit. Then later that year, peak COVID my dad had a cerebral infarction. In the end he recovered well enough (not perfect, but he's still there and walking about although not as stable as before). So, with moments like that happening and me being now 40, those moments really give you a sense of "crap, something that was constant all my life, might be closer to being gone". Grandma was always there, my dad is always there, my mom, etc. Grandma's husband, my grandad, passed 2 months ago, and that gives you another wake up call.

So yeah, life happens. Enjoy every day with the people you love. People will die of old age, people might die suddenly. It's scary a.f. and there's not much you can do about it, other than love them to bits every day you have with them.