Sounds very familiar. For about a decade, I was in the best job I’d ever had. I was great at what I did and was also regarded as the best person for the new comers to learn from. Then the company decided to start forcing square pegs into round holes just at the start of the pandemic. I was moved from the fast paced reactive role where I exceeded to a project management role with no support for learning the policies and procedures that were new to me.
Long story short, two horrible years of stress where I was was still trying to do my best and making myself unwell trying.
Based on what I learned from that times I’d advise seeing the doctor and using any formal process your company has. Use your union if you have one although my Prospect rep was totally useless.
You may be one of the lucky few who works at a company that will listen and help but in most cases, they only pay lip service to employee care and mental health. It’s important to realise that this is the beginning of the end with your current employer. Start looking for a new job. Given where your head will be, this is easier said than done.
I now work somewhere where the knowledge and expertise I bring a massively appreciated and there’s so much less stress. Interesting, the old place is still hemorrhaging staff and still unwilling to acknowledge why.
Best of luck with it.