The human body is complex, a chemical factory with many processes. If you have a flaw in it , you get medicine. Working maybe good for the error, but always has side effects. No clue what kind of medicines you have. A doctor just gives you the candy and never speaks about it, but then you read about it and your mind setting is going down. So I know and try to fight the knowledge I now have, however cant reject all. There are some really troubling issues with my medicines if process go wrong. However you are getting older as wel. And everybody is unique. Not long ago, they find out, women are totally different then men, though we have a lot in common as in organs and working principles. The strongest instrument is your brain ! You can change mindsets. Fi you lie down now in the way you feel. I know all not easy, I also ignore things , I should do but dont. Only if I really put on another mindset, it changes. Just force. You do your 5 km walk ! You force yourself to do it ! Maybe then lie down, ok but instead of all afternoon, short it to an hour and force yourself out and do something else. In Thailand after a cold shower, I stand naked in front of a running fan ! leftover water (filmlayer) evaporates and cools you down. After that I really feel "reborn". Well thats for me personal. Once I tried and made me feel real good, so now do all the time. It works for me. Positive mindset. As advised maybe do 2 times walking and half the distance? As I said, I know, not easy when you are running in a different mode. Your brain can be your friend, but also your enemy.