Hi Sweettooth,
I think you may well have an adrenal problem following covid/vaccine.
I test my cortisol and Dhea about twice a year. Tested in January and my cortisol was fine apart from slight lunchtime dip.
Got covid early May and once usual symptoms gone I continued with severe fatigue so I tested again. Guess what, my cortisol was practically nonexistent.
It sounds like you’re having a bit of a yo yo time, fine for awhile and then probably because of stress, inadequate rest your crashing again.
Could you afford to do a cortisol and Dhea saliva test, which will test 4 times a day?
I use this company which is uk based but they send it to the States to zrt labs to be tested and you get a full report. They are called
Hormone Lab uk (zrt labs)
If you Google them you can see a sample report.
In fact anyone continuing to suffer fatigue from long covid should try and take this test.
Hope this helps and good luck to you xx