Does anyone make up scenarios that are nearly impossible to actually happen but your brain justifies them?

As in, you know event x is incredibly unlikely to actually happen, but your anxiety keeps making an argument for how it could actually happen. I'm struggling with this right now, and I could have literal proof that my fears are irrational, but my brain keeps on going "what if" and finds a way to make it seem to be the likely outcome. It's driving me crazy and idk how to stop it.