I could have written this post myself. In fact, I came on here today looking for validation because I think I want another child, but I don't want to risk the PND again.
I'll be 37 this year and my DD will be 3 in a few months. I think my PND was caused by a number of factors - mainly a hormonal imbalance/sensitivity. I'm still breastfeeding (just a morning and an evening feed), but I think the hormones involved are still affecting me, so I'm not quite back to being me.
I genuinely don't think people can fully understand this unless they have had severe PND; it took me a long time to realise that what happened with me wasn't 'normal' and that whilst having a baby is difficult, there is a difference between being tired, for example, and being PND tired.
I've been told by countless people that it's OK to not have another. That I don't have to risk my health. I've read books about only children and how they often grow up to be happier and better adjusted and more successful than kids with siblings (I'm not saying that - the books/research/statistics are!) And yet...I still worry that my little one will be lonely, or deprived of a sibling if we don't have another. I have two brothers and we had an amazing childhood together.
More than that, though, is the fact that I would have another child in a heartbeat if I could skip the newborn phase - but that's because I associate it with severe illness. If I could guarantee I wouldn't get PND again, then I'd be more willing to go through the sleepless nights and the physical toil. But there is no guarantee.
Sorry I can't give you a better answer - but I did read somewhere something along the lines of, "The perfect amount of children is the amount you have." I think it means that you'll be happy with any children who come along, but also that you could be happy with the child you have - each family is different and you have to do what's right for you and yours. If that means safeguarding yourself by staying healthy and happy with one child, then you should do that. (And I should maybe take my own advice and stop worrying!)
Xxx