I had a mercifully brief episode of postpartum depression after DS6 was born. It felt like my soul and my spirit were paralyzed, not just metaphorically but physically. I ~wanted~ to feel the joy and bliss of having a beautiful, healthy newborn, but it just wouldn't come to me.
What compounded the depression, for me, was the very fact that I - a Registered Nurse - couldn't pull myself up by my bootstraps and just snap out of it. If I couldn't "fix" myself, how could I ever help anyone else out, ever again? The PPD was feeding upon itself.
I did start to feel better after I learned more about PPD and understood that it was common, and that it was real. I guess that newfound knowledge made me realize that I was not a monster, nor doomed to be a terrible mother. It was just the result of a temporary (for me) neurochemical imbalance.
It must be terribly frightening and frustrating for you, Susannah. I concur with kittycat45 that your DH's current medication may not be the appropriate one for him at this time.
Also - and I don't mean to put too simplistic a spin on a very complex condition - there is a body of research which suggests that moderate aerobic exercise can help to alleviate some of the symptoms of depression. Does your DH play any sports? Does he have any friends that you could call upon to invite him out for a game of tennis or raquetball, for example?
I'm sorry that I don't have any more concrete help for you, Susannah. You're in my thoughts.
Rose