My daughter just turned 13 months old and I continued to nurse her before and after surgery. I didn't breastfeed her during my 2 day hospital stay but once I came home I started up again. My calories don't affect my milk supply and the first week after surgery I was barely producing anything but I just kept putting her to my breast and eventually my supply picked back up. My advice is to keep putting your baby to your breast as much as possible and soon your supply will catch up. I also don't pump, so I have no idea how much milk I'm producing but she seems satisfied and I feel the let down which is a really good sign that I have a good amount of milk.
Also breastfeeding is about supply and demand, the more you breastfeed the more milk you will produce and don't supplement with formula until you've built up your supply. With a newborn baby they are going to want to eat every 30-60 mins. Just keep switching breast after every feeding. I've breastfed all 3 of my kids until they turned 13 months old. Also I still have fat reserves on me that my body can tap into if my cals are low. Also check out the kellymom.com website it has a lot of good info about breastfeeding and calories, etc. I haven't looked at it in a while but basically it says that calorie intake doesn't affect milk supply. Your body will find a way to produce the milk. Good Luck
