damodad,
Lots of good advice here already. The thing with PND is, (another one here who has had it), that you dont actually realise you have it for quite some time, and the very nature of the illness means it exacerbates all situations, emotions, fears etc.
So often it feels like you are incapable, or a crap mother (and of course everyone else looks like they are coping marvellously, besides, even if they werent - they wouldnt say so, because, well, you arent allowed to say that........)
It is quite common to crave company, but to subconsciously withdraw from family or friends because you feel so crap/needy, or that they dont care/like you.
The most important thing for me when I was diagnosed, was my DP understanding how I felt (although I know that those feelings although very real, were very much exaggerated). I couldnt just go out for a lovely walk (didnt want to leave the house - too much trouble/hassle/had no energy), I couldnt just "cheer up/get my act together" because that is not how PND works.
What made it difficult for DP to realise what was going on was the fact that I was 100 times better when he was around, the pressure was off, he did all the driving around etc and it just made a huge difference. When he walked out the door for work each morning I would literally go to pieces. I called him home quite a few times on what could be considered quite spurious reaons. (Once because DS had been sick, another time because the very first time I left DD alone with DS - it was literally about 30 seconds - she had tried to feed him some blue playdough when he was about 2 months old and he half choked on it).
When I was diagnosed he made a specific point of telling me every day that he loved me, and that i would get better. It made a huge difference to me. He wasnt over keen on me taking Anti-depressants (his mum was chemically addicted to valium), but Anti-depressants (these days for sure) are not addictive. I take Sertraline, and have done for 18 months now. Within a few weeks of taking it I felt hugely better. Its a long process, and you cant just stop taking ADs which is why i am still on them.
I personally, didnt need counselling (although this is very helpful for some people, and may be for your dw as I would imagine having a baby has triggered some memories and fears regarding her own childhood), because I feel mine was purely a chemical imbalance triggered from hormones changing after childbirth, and the prolonged lack of sleep.
Sorry this is quite a long rambling post, but, I believe that the more stories you hear the easier to grasp it, and also, it helps other sufferers to know that it is an incredibly common illness for new mothers.