If its a professional job and a professional company then you need to take the doctors advice and take what action is immediately important to your health – that is the first priority.
If that is a week or two off work make sure they are told the simple medical facts why you are off. And nothing more.
Meanwhile get your thoughts together, what are your REAL alternatives.
I have been a similar situation a few years ago, it did not need medical treatment so not as bad, but pretty bad. I talked to the most senior person in the company who agreed an action plan.
3 months later the plan had not been acted upon, and after several more conversations myself and wife decided resignation was the best option.
Be very clear, this is not redundancy, you are not entitled to it.
However if you wish to pursue constructive dismissal that is a route that is open to you, but not without heartache and hassle.
The option I took is more common in professional arenas and we agreed a compromise agreement, this is where you and the company agree a (usually tax free) termination payment. The minimum is your notice but you can ask for more if the issues run deep and it would be hurtful to both parties for bad mouthing to go on.