No, No, not everything works for everyone. That's why you have to try everything. The exercise is a #1 mood stabilizer, but what I am telling you isn't just what I "prescribe," it's based on personal experience. Anyone who knows me, knows I am a type A person. But now, I'm a calmer type A person, and the reason is that I experienced the same thing that you are dealing with, aftr I had been riding about 6-7 years, probably at my peak. I really suddenly lost all of my endurance from a combination of some undetermined immunological disease process that comes out under stress, retiring, and resultant anxiety about all of it. I was thinking almost exactly what you said in your above post. I kept going to yoga, and I found teachers who were both mind and body focused, so I actually felt like I was exercising. It calmed me and I gained a lot of flexibility and balance, something missing when you just ride. Then, I signed up for a Mindfulness Stress Reduction class. It was 8 weeks, and I was not a good student, in that I felt agitated during the class (we had to be silent for one whole Saturday session. I cheated and called my son), but I did go home and do the homework. When the class was over, I kept doing the shorter meditations and visualizations. I still do, but not all of the time. I also went to acupuncture and had some deep tissue massage/PT.
I am not sure what really worked, because I was doing so many modalities at once. But after about 4-5 months, I felt better (I did take some meds for a short time), I was able to make the decision to go back to school the next fall. It was cycling season again by the time I started feeling better, and this was the summer I did all kinds of slower, shorter rides. I also found that during that winter, x country skiing didn't bother me at all, and I felt better after heavy exertion, unlike cycling. I never got quite back to where I was in speed, but I am very close. And, I am 8 years older now, and I'd say, I'm pretty good for my age, and the kind of riding I do. The goal is to keep riding until I keel over, and not beat myself up about some arbitrary number.
I am betting you might like something that is more movement oriented, like Thai Chi or Qu'i Gong. While these help calm the brain, they are active and a good complement to endurance sports.