Yeah, I also suspected a vicious cycle of stress/cortisol causing poor sleep, which leads to more cortisol and poor recovery.

It did get better when I stopped cycling, as much as I loved it. I'm now walking instead and feeling much better. I intend to increase volume over time and once my VO2Max is back to my baseline then I may introduce cycling with an eye on going easy and eating enough before/during/after exercise.

Thanks for the advice, it is good to hear that it worked on other people.