When an over active imagination turns into catastrophizing, okay. If it's not taking up too much space or time, it just means you are prepared for whatever happens; you've already imagined all the outcomes. When catastrophizing turns into anxiety? That's a problem.
I've got my main bujo for scheduling and shit. I haven't touched it in a few months but it's on my to-do list to start doing that again. Real soon now (tm). Natch.
I got a second bujo for just writing shit down. Brain dumps. It really helped with the anxiety-inducing scenarios. I'd start a new page, title it with the pending disaster:
Party on Friday
Then I'd list all the bad things that I was fearing:
Say something stupid, everyone thinks I'm weird.
Get stimulus overload and have to dip without saying goodbye to anyone; they think I'm weird and don't like them.
Party gets invaded by ninjas, we all get mown down in a hail of throwing stars and swords.
Then I'd list the likelihood of each event happening: 50%, 100%, 1%
Finally, I'd list the actual, real fallout of each event:
They already think I'm weird.
Ditto above, and they know I like them and often dip early.
Death.
Then I really assess how bad it all really is. There's a not inconsiderable chance that I remind everyone that I'm odd at social functions and a non-zero, but very low chance that I die to ninja attack. Okay. That's all doable.
It eased the anxiety for me a lot, let me get some things done that I was struggling with.