Butters, it's indubitably very difficult to do but I think it might really be a good idea if you'd explain to your employer what you just explained to us. He can't look into your soul and therefore needs you to explain so that he understands. As long as he can't understand, he'll keep raising the pressure.
And if he understands, perhaps you could be moved to a different line with a different line manager when you return? (In that case, I'd recommend you meet the new manager over a pint and explain the problem to him in a relaxed atmosphere and on neutral ground. That'd secure you a good position for your re-start.)
PhantomFan, welcome to the board

It's always great when a lurker chooses to de-lurk.
That situation between you and your wife looks to me like a classical negative feedback loop. I think it might be a good idea if you had the same therapist or if your respective therapists would meet and devise a common strategy. Or, ideally, you might make a therapy together, as a couple. There are strategies to counter the negative feedback in a relationship and to go into a positive one, I've read, but being single my knowledge about that particular aspect of life is of a rather theoretical nature.
Scribble, great news about you being on 4 wheels again! =) How's your mom holding up in the chemo? My aunt and mom both had chemos and they agreed that ginger in any form is an excellent remedy against the sickness caused by the drugs. My personal favourite is chocolate-coated candied ginger while my auntie loved ginger cookies and my mom prefers ginger tea. But really every preparation of that root will help.
Btw, it's also a reliable remedy against PMS and travel sickness. I use it for the latter purpose.