Why multitasking is bad for my mental health

I am getting older and wiser... I do not enjoy multitasking anymore. It exhaust me and confuses my mind. It triggers my OCD because doing many things in one day and not fully completing them leaves open loops in my mind. I enjoy working on less tasks for longer time every day, taking advantage of the higher focus and efficiency. Well, I am not yet able to work like this most days but this is the direction I want to take. Because multitasking is not working for me. Not anymore...