It’s a really shifty spot to be in OP, and I have been there.
Can you possibly take 6 to 8 weeks off? A school holiday length of time will give you a decent rest (if you think it’s too long, it’s a lot shorter than taking a whole year off if you really crash).
Once you’ve had a week to stay in bed, could you go on retreat for a week or two?? Somewhere really gentle to recharge your batteries where there are no phones or distractions.
Medication might help. Talk to your GP. It doesn’t have to be long term and it could help you put your head above water.
Cut all the stimulation and distraction you can - lock you phone away except for calls, stay off social (including mumsnet), limit TV, esp late at night. Dump all social pressure for a while.
Add in as much fresh air and nature as you can - walks, gardening, a weekend on your own in a cottage by the sea.
Get rid off all the stress and complication you can - can you cut down to 4 days for a bit / get a cleaner / dump cooking / reduce demanding social events - you can slowly add things back in as you get better, but cut for a whole
Once you’ve had a rest (and only then) you can start to build in habits that are helpful (Ranjan Chattejees stress book is a good place to start - but I’d honestly give your self a months complete rest before you try anything)
You can get over burn out but the only way is a rest, and a very graduated reset. You need to do less for a good year or a little more - and you will need to make some long term adjustments
In the mean time go see you GP,