Always have been.
I'm a hypochondriac. Fortunately not the annoying kind that regales all and sundry with my fake aliments. No, I just worry about my imaginary symptoms, silently torturing myself with the logical consequences and my inevitable unpleasant demise, until the next fake symptom shows itself and I switch my allegiance to another imagined doom.
I worry I'm on the wrong train with increasingly disastrous consequences, or that any one of a number of minor disputes is going to spiral out of control into epic proportions. And these are not idly sketched worries - I worry in full technicolor, I have plots and characters. I have death scenes, emotional goodbyes, unexpected alien landings.
I have always hated phone calls. It's likely some form of extension of my general social anxiety, but honed into some special aversion for voice-only communication.
As a teenager I got into the habit of imagining and rehearsing the opening lines of any upcoming call in order to delay the inevitable awkward silence. These anticipated dialogues extended far beyond any possibility that my prediction of the conversation would reach.
I expect you've already seen where this is all going.
Worrying is, at least for me, a shorter way of saying "being tormented by an overactive imagination". My worrying has been a training ground for writing. It's given me somewhere to practice dialogue, arguments, storytelling etc.
When I write it's almost as if I am "worrying the page" instead of myself. Writers often say that they are driven to write. I get that. If you have a hosepipe that won't turn off, then turn it outwards and water the lawn rather than trying to drink it all or shoving it down your trousers.
Storytelling is an outlet for energies that can otherwise turn destructive.
We have a puppy. If I take her for a run in the park she will loll about for the rest of the day, relaxed and sleeping. If she doesn't get to run that energy out of her legs she'll find a shoe or a pair of glasses or my headphones and chew them up. Same thing.
So, yes. Worrying isn't a good thing, but it's something that I'm willing to bet many writers are world class at. And it's a great training ground!