Sympathy for your tough situation. You are trying to do everything reasonable to get a good outcome, so there is nothing to blame yourself for. Have you thought about practicing meditation, which can be as simple as some quiet time in which you relax and focus your mind elsewhere?
The one approach that helps me the most in dealing with serious horse health issues is realizing that there is an element of probability and unpredictable outcomes in dealing with horses–we can purchase wisely, provide the best care, and still wind up with a serious problem. Each horse is basically to some degree a gamble, in which we can improve the odds in our favor but never completely control the outcome.
Right now, the highest quality and most expensive horse I have ever owned is facing an uncertain future because of a pasture accident, at a professional farm that provides a high standard of care. There was no way to foresee or prevent this, other than keeping the yearling in a padded stall 24/7. Given that type of event, and that everything was done medically, I try to remain as emotionally detached as possible–it’s just basically random chance and probability that this happened.
Here is a video that explains this concept, albeit regarding trading financial instruments–by analogy, if we are good horsepeople, by using our skills, most horses we work with will have good outcomes, but every horse carries with it an element of random chance and might through no fault of ours have a medically or otherwise complicated history. Given the element of probability and random chance, we can’t blame ourselves and therefore anxiety should be lessened.
Stock trading psychology