I have never had this problem with playing music, perhaps because I don't play enough, or fast enough, for it to surface.
But - I am a programmer by trade and I type a great deal and very fast, with a lot of keyboard shutcuts, etc - quite similar to playing an instrument, really. I learned touch typing years ago and worked on it until I acquired the skill and it became automatic. I have been doing it for up to 8 or 10 hours a day for almost thirty years now, and I can literally do it in my sleep - I've actually done that. (The code wasn't very good but the problem was not typos!) .
Once in while, I'll get into a sort of rut similar to what you are dealing with: I will start to think about each keystroke I'm typing, and then I can't type anything correctly at all.
It seems that once you learn how to do something by reflex - involuntarily - applying conscious effort to that activity disrupts the reflexive patterns, and your efficiency and accuracy take a nose-dive.
They often say about athletes, particularly slumping hitters in baseball (At the moment Aaron Judge) : "He's trying too hard". It amounts to the same thing: Applying conscious effort to something that should be natural and involuntary. Hitting a baseball moving at 90 MPH is very difficult and it requires a great deal of practice to acquire the skill. But once you've got it, thinking about it ruins the whole thing.
The solution in baseball and also for me in typing is to "let it come naturally" - that means RELAX, and take your mind off what you're doing physically - let your body do the work.
Of course it is more difficult than it sounds: You tend to get into an "infinite loop" - an OCD thing: You are worried about your problem and so you focus on it that much more, thereby making the problem even worse.
When it happens to me, I generally "relax" by focusing deeply on the work itself - the programming task or problem I'm dealing with. My mind gets completely occupied with that and I stop thinking about my fingers.
In your case - you say you've tried something like that and it's not working - the solution might simply be to take a break from playing for a few days - just do something else entirely. Eat,sleep, ride a bike, watch TV, hang out, go skateboarding - whatever floats your boat. That will break the vicious cycle of obsessing over your hands. You will come back fresh with a slightly different outlook on what you're doing on your instrument, and you'll be a little rusty, which will help to level things out, as it were.
Note: There is also a variety of the hemp plant that is highly valued for its medicinal and therapeutic powers.
Its use is quite popular among musicians, and its judicious consumption would likely be be very helpful to you.
However, its possession is illegal in must US states, so I cannot recommend it.