I do this, a lot.
"What if me/my mum/my child get hit by a car on the way home from school and no one informs us?"
"What if I get so poorly that I can't ring the school to let them know and my son gets upset and he thinks I've abandoned him?"
Or if there's a crash somewhere on the other side of the city, I think "oh my god what if that had happened near my son's school and he got injured/killed?"
I am in therapy for it but what my therapist doesn't seem to understand is that when I'm in a full-blown panic or a meltdown, I literally cannot rationalise the situation and I end up sobbing.
My mum often picks my son up from school and if she doesn't text me by a certain time, I start thinking she's fallen ill or that they've been hit by a car.
It's fucking awful, and I wouldn't wish it on my worst enemy. It got worse after our family dog died suddenly. Well, it wasn't THAT sudden - he had dementia and arthritis and was gluten intolerant, but they decided to put him down when we weren't expecting it.
I empathise with you OP x