Hi Garry and welcome to our forums
It is good you've found your way here. There does seem to be a bit going on for you at the moment. Have you every been diagnosed with a mental health condition? E.g. anxiety or depression?
I'm no health professional so unable to give you a diagnosis of what's happening with you. Though I do have lived experience with PTSD, anxiety and depression.
It would be best to go to your doctor to talk about it and get a medical certificate.
So do you tell your boss or not if you have a mental health condition? That's a really good question, so thanks for asking.
During my working life I frequently had days off because of my mental health. Though I never realised this is what it was. Always put it down to a 'viral infection' that would pass in a day or two. This went on for years. About 15 years ago though the days off turned into a week or two. The doctor didn't even diagnose it then - just that I needed time off work to deal with things and to recover. That particular boss wasn't very happy and used to say - when are you going to be okay to return to work.... Fast forward to another boss. By that time it had been finally diagnosed and I did tell her. She was extremely understanding and supportive!
However, others here on the forums have a different story about how their boss responds. My thoughts are it depends on who you work for, whether the organisation has good HR policies in place, particularly around mental health. It might be or might not be detrimental to your career. Just depends on the maturity, understanding, knowledge and experience of your boss. What is your relationship with your boss like?
Maybe once you start looking at that relationship it will help you to decide on the course you should take. If you don't think your boss will be understanding - You could do like I did for a good 40 years of my working life and that was say I had - gastro, or viral infection (aches, pains etc). Which in some ways was true in most instances.
Hope this helps in some way Garry.