The best advice I've gotten repeatedly (and it is actually something Tracy believes as well) is that you need to do what works for the family. Yes, bf is best, but not if you are in pain and completely stressed out. That simply isn't good either. And, from what I understand, it can be harder to bf with a toddler around wanting your attention too.
You might consider (just consider) giving it a go. This time it might fall into place and be a breeze. But, if not there's no harm done. And, if you don't want to even give it a try, you're still a fantastic mom! I think it's great that you're thinking about it now so that you are prepared (not sending DH out for formula in the middle of the night) and not adding stress on yourself during an already emotional and stressful time.
The only bit of advice I have is to think up some witty replies to shut up the insenstive moms, nurses, family, etc. who might raise a brow or try to second guess you. I don't have anything now, but I'm sure the other moms will be able to help.
Don't stress about this! Enjoy the baby dance and focus on making that baby! Good luck!
PS: LIke other posts, it didn't work out for us - too exhausting and a very large/hungry baby with my milk trickling in. Once we started formula, it was just so easy and she was happy not to be starving all the time. Plus DH can help. My DD is very, very healthy and growing and developing just fine!