You'll have to talk to your senior management and tell them that they have a choice, do without you for a week or two where you recover, or do without you.
If you think that your job is too stressful, then there are two things you can do: Reduce the stress, or find a job with less stress. That's something you need to talk about; either your management finds ways to reduce the stress, or they'll get into a lot more trouble by losing you altogether.
Remember that working over 40 hours a week is not only bad for you, it is also inefficient because your productivity drops.
One thing that can reduce your stress is just to mentally accept that you will be leaving, maybe not right now, but you will be leaving, and if there is politics going on and people are highly opinionated you just don't give a ****. You know you can leave and leave it all behind you. You know you don't have to care. Do a decent job, and don't care about what people want.