I'd say give it a go, and see how you do - as others have said, this baby may well be totally different to your first, and your reaction to the birth might well be different too.
But if you decide that it's not working for you, then use bottles and be happy with that decision - all three of mine were bottle fed because I had problems producing enough milk, and they are all fine strapping lads with no health issues whatsoever. You can make yourself feel better (if you need to) by making lots of lovely home-made vegetable and fruit purees when your new dc starts weaning.
With regards to the PND - can I ask if you have spoken to anyone about preventative treatment?
I had PND after each of my three ds's, and there was a progesterone treatment that you started soon after the birth (I'm sorry I don't remember any further details, but ds3 is 11 now, and my memory is not what it was .
At the time, I attended a workshop by a noted PND expert, who believed that low blood sugar contributed to PND, because if your blood sugar dropped too low, then the receptors in your cells that are programmed to receive progesterone will switch over to being glucose receptors - because your cells need energy more than they need progesterone. She said that once this had happened, the receptors could take days to switch back. She recommended eating some carbohydrate within 1 hour of waking, every three hours during the day, and not more than an hour before sleeping - in order to maintain your blood glucose at a sensible level - not too many peaks or troughs. If I remember right, she suggested carbs that would break down fairly slowly, not sugary/sweet things.
I only mention this because it is a drug-free method that you can try for yourself - and as far as I can see, it carries no risks with it - she wasn't suggesting loads of carbs, just spreading them out through the day, so you needn't gain weight either.
I hope this helps.