The moment I lie down, my head gets louder
It's manageable while you're busy. Then you lie down and the footage starts playing on its own — was that the wrong thing to say today, the thing you have to handle tomorrow, a scene from years ago that's long over.
It isn't that you don't want to sleep. You can't switch it off.
Sometimes you even get angry with yourself: this doesn't matter, why am I still thinking about it? And the more you tell yourself to stop, the clearer the voice gets.
What may be going on
Circling thought usually isn't overthinking; attention has been caught in a loop with no way out. The body is trying to solve the problem, hoping to find a safe answer, so it keeps the thinking running.
This isn't a fault. It's closer to a form of protection — afraid of missing something, afraid of being unprepared. It's just that this kind of protection also keeps you from really resting.
So this isn't going to tell you to stop thinking. When you can't stop, ordering yourself to stop usually only adds a layer of frustration.
Essences that may fit
You don't need all of them. See which description comes closest to how you are now.

White Chestnut
Thoughts that won't stop circling
The same thing turned over and over, a voice in your head you can't switch off. Its support isn't in stopping the thoughts but in letting the body slowly feel that not chasing them is still safe.

Aspen
Unnamed fear, vague unease
If the thing turning has no content you can name — just a suspended unease — this one comes closer.

Clematis
Daydreaming, living in imagination
Sometimes thought isn't going back over things but drifting elsewhere. The body is here; you aren't.
One small thing you can do now
When you notice the thinking going round, pause first.
Let your attention rest lightly on your head or the rhythm of your breath. Don't change the breathing — just know that the body is breathing.
Let the thoughts be there and let the body be felt at the same time. It isn't one or the other.

When your chest is tight and you can't stop
Neiguan PC-6 · Inner wrist
