Phil's suggestion of educating your employers is good advice. I took this approach over 35 years ago and spent the rest of my working carreer with the same company.
Once my boss and all the managers in our company understood what I was going through, I started to receive much more support than I knew what to do with. Rather than me having to leave when the pain got too bad, it was usually the other way around. One of them would look at me and suggest that maybe I should go home for a couple of days but I would only follow their suggestions once in a while just to show that I wanted to get the job done.
There is really no reason why all employers couldn't have the same level of support for their people.
George
Breb Assyl