There’s not enough context of you here. Our ability to think clearly is predicated on a lot of stuff, almost all of it psychological and lifestyle but some hea

There’s not enough context of you here. Our ability to think clearly is predicated on a lot of stuff, almost all of it psychological and lifestyle but some health and genetics. Are you depressed? are you burning out? Are you eating well? Are you exercising? Are you disengaged? Are you socially engaged? Are you anxious? You need to step back from the tasks you’re finding difficult and look at yourself not as a programming machine but as a biological entity with a complex giant dna mutation brain that can easily get thrown off track due to any number of factors. Most likely unless you’re developing some sort of early onset brain disease you are depressed, anxious, burning out, or simply aren’t interested in what you’re doing. By 40 things get complex because the newness of “OMG IM AN ADULT” wears off and just simply working isn’t enough, especially in a task that requires “flow” of intentful mindful engagement. I suspect you need to step back for a bit and look inside yourself very critically and examine what’s going on. To me it sounds like probably a mixture of all of the above, leading to a growing burnout. My suggestion that worked for my burnout is take up a rigorous practice of vipassana meditation, regular exercise, managed diet, and rigorously constraining work focus to when it’s appropriate and otherwise entirely letting go of the pressure to perform. Then when working not engaging in second guessing your output - we have ups and downs, the important part is enjoying the process of programming. But YMMV, I would start with taking those questions above and asking the people closest to you them and take their answers seriously, see a doctor and explain your challenge, and see a psychologist and explain your challenge, and spend time seeing yourself for who you are not who you think you are. Good luck!