1) Started after a period with lots of infections and the diagnosis of a PAD. 2) Exhaustion, concentration difficulties and lower back pain. 3) Predictably starts after 5 hours mental work, only ends after a full day of being able to do nothing. Physical activity, like walking for upto 2 hours (the furthest I get to), also starts it. 4) Directly related. 5) The 5 hrs activity limit. Just had to quit an part-time job where at times it exceeded this limit to avoid it in the future. 6) Also whenever I'm not able to get at least 10 hours of sleep, and an additional 2 for slowly waking up.