susanmt - you are not alone! far from it - there are so very many of us suffering pnd.
one of the hardest things is to admit that there is a problem at all. and admitting to health professionals is different, i found, to admitting to yourself. when my ds was about a year old, a friend had a baby and for various reasons i thought she might be developing pnd. i remembered how i felt it impossible to admit to a serious problem when everything went to pieces for me and thought that maybe she might feel that way too. so i gathered a few scraps of courage and told her about my depression. we had a brilliant chat and although i'm not sure whether i helped her, i felt marvelous afterwards.
suddenly i realised that there is no reason to feel ashamed of myself, or that i am a burden to anyone. it's perfectly normal to have pnd, it's like having greasy hair - only a zillion times worse!
you can feel proud of yourself - it's hard work to be a mum. the hardest times are on the bad days, but there will be good days as well, and the good days do gradually increase.
here's a strategy for when you're down: when you're not feeling to bad choose a memory of something that you did that fills you with joy or laughter or pride, anything at all, and think about it so that you remember it. then, when you're really low, take 5 or 10 minutes to concentrate on that memory. i mean REALLY concentrate on it, go throught the event step by step, recall what you were wearing, what you did, what you smelled, what you saw, heard, said.
this works, it really does lift you.
and another thing that i find helps (i know, i'm having a right old waffle) is to decree a baby-free zone with dh. the baby is asleep, the chores are done (or they WILL wait!) and for the next two hours we will not do or mention anything to do with babies, our's or anyone else's. at first we didn't know what to do with ourselves and just watched tv (that in itself was bliss!). but then we realised that it was counter-productive and we try to have a baby-free zone at least once a week when we don't watch tv or read our own books. we talk about things we did in the years BB, and what we would like to do, we give each other massages, we read the papers together and talk about the world, if we can we might go for a walk together and then we have to make a real effort because all we can do is talk. it's brilliant!
anyway, my burble is over. log in and talk, because it may help you, and it will also help others, i'm sure.