I retired early last October due to ill health. I had a cancer diagnosis in June 2023. I had chemo toxicity which made me seriously ill and ended up being off sick for 6 months, after which I went back part time. I then started another medication which had dreadful side effects, which I struggled through, reducing my hours further, until I finally decided to retire. My husband is already retired, I don't get my state pension until next July, and my PIP application was turned down, so things are a struggle, but it has got to the stage where I couldn't do anything at all except work, and I wasn't doing that very well. My days off were spent recovering, and then it was back to work again.
I am older and was already planning for retirement, but it has (literally I think) been a life saver. I now have enough energy to do a little exercise and to enjoy time with my family. The more I do, the more I can do, and I am enjoying my hobbies again. I still have a nap in the afternoon on days when I have done more physically strenuous things, or if I'm planning on going out in the evening, and there are still a lot of things I can't do, but life is very much more normal now.
If I was you (which I'm not) I would take some time off sick and arrange to go back part time afterwards, if possible. If you're on PIP you will be entitled to extra consideration under the Disabilities Act, and your employers will be obliged to consider any application for reduced hours seriously.
if you carry on as you are you will not be able to work or to help with things at home, so to me it's a no-brainer.