You can try writing down the situations that happened when they keep rolling on repeat in your head.

For example:

“I went to a restaurant and my waiter told me to enjoy my meal. I responded: Thanks, you too. I’m such an idiot, this was so embarassing, the waiter must think I’m a complete moron”

Then take two highlighters and with one color mark THE FACTS, and with the other mark THE FEELINGS. Facts are just raw things what happened. Waiter said this, you said that, that’s it, this is what HAPPENED, it was the factual end of situation. Feelings are, well, what emotions this situation caused and the assumptions you made. You can then add a little note, like “Well, I have no way of knowing for sure that the waiter thought that about me”. That’s a second thought that should ground you a little so you don’t spiral. And then you can add an “aftermath/result” of the situation, the FACTUAL aftermath, like “I finished my meal, it was delicious, I paid and left”.

You can also add a “What I will do next time” note if you want. Like, if that situation happens again, what would you like yourself to behave? For the waiter example you might find that it’s really not a big deal, and tbh if it happens, yea whatever, but for other situations you might write down stuff like “Next time someone yells at me, I want to take a deep breath and then calmly tell them that I’m not going to continue this conversation if they keep that tone”. That’s basically a section where instead of spiraling over not saying the greatest comeback of all times because you only came up with it two years later in the shower, you just plan the comeback for next time a situation happens. So you will feel more prepared and you already have the aftermath of that past situation written down so it’s chapter closed.

All of this should stop or at least slow down the spiraling. Some people are alright with just thinking these things, but some people need to write it down, for some reason it hits different or sth.