@chessmaster777 According to a few good sources, including Cleveland Clinic (which I really like for straightforward medical information!) any given person's miscarriage risk in the second trimester is between 1 and 5 percent, and that range will depend on a variety of factors specific to the person (age, other health issues, etc). So your personal risk of miscarriage after 12 weeks is statistically quite small, even if you do have some of those risk factors. However, about 20% of all miscarriages that occur happen after 12 weeks--so when you are hearing specifically about miscarriages, miscarriages after 12 weeks might SEEM overrepresented--but again, that's in talking about miscarriages that DO occur rather than simply risk of one occuring at all.
The other thing that I think happens (at least, it sure does to me!) is a bit of confirmation bias--you start to believe the thing you are worried about is definitely true and suddenly you see it everywhere. Our brains are already prone to confirmation bias because we LOVE to seek patterns, but you know what I think makes it infinitely worse?? Finely tuned social media algorithms. If you watch one Instagram reel all the way through with hashtags about late miscarriage, you know what Instagram is going to think you want to see more of? Late miscarriages! Suddenly they will be HUGELY overrepresented in your slice of life because the algorithms have decided that's what you want, and it is a tall task convincing your brain that this doesn't mean they are super common.
I know this response isn't exactly what you are asking for, but I hope it is a bit helpful. I am a person who has lived with general anxiety disorder for as long as I can remember and one thing that has hugely helped me to control and regulate worry spirals is learning to frame the world around me using logic and statistics (in addition to still very much valuing personal stories and anecdotes).