Actually you should take more water (warm water in the first month), and take more rest.
I have experienced that even you didn't eat something wrong, still not enough breast milk, it was because I have not enough water intake and didn't sleep well.
Soup is important because it is also a source of water, so remember to drink more water.
I found that the baby poo poo will be very smelly when the baby is drinking formula milk, you are now giving formula milk more than breast milk, that's why the baby poo is so smelly.
Just try your best, but don't give yourself too much pressure, just take it easy, if you feel stress, there will be no breast milk.
Good luck~
p.s. here is a website about breast feeding, hope it can help you~
http://www.breastfeeding.org.hk/ 
