I had this once before - different situation - but a real shock to the body that then morphed into this kind of stress related exhaustion afterwards. So I am applying the same techniques I used then and thought I would share them with you:
Do everything that is important in the morning, and try to leave the afternoons free if it is possible
Prepare dinner in the morning, and if you have a slow cooker or other ways of cooking dinner in the mornings, so there is little or nothing to do at the end of the day
I took to showering the dc in the mornings so I didn't have to wrangle with the children in the evening. A quick hand, feet and face wash was so much easier
Close the curtains etc early and bring everything forward
Don't commit to big day outs or any day out. If you have the energy then go on the spur of the moment and just for an hour or two
Take vitamins every day, eat well and try and sleep as long as you can
I know just what you mean about not being able to rely on your own body, I feel the same. I can't make arrangements with anyone because I am worried I will have to cancel, or worse to feel like this whilst out.
I am watching others motoring on, and wonder if this is yet to come for them. We are all at different stages, and maybe they are still in flight mode, I know I am feeling less stressed now, so I have begun to slowly relax and this is when the problems started. In the peak of the pandemic I was flying high! I was up all night getting shopping slots, running around all day delivering shopping, looking after dc, cleaning. A nervous energy that slowly depleted every ounce of my body's resources.
Would be glad to read any other suggestions for how we deal with this.