Liz, thanks for mentioning the "sleepy hormones" - I forgot about that one! Interestingly, studies have shown that parents of bf babies actually get more sleep than ff babies, even though bf babies often feed more often! The sleepy hormones which put both mum and bub straight back to sleep after (or during!!) a feed are probably a big part of this.
The nurses were always happy to see me drifting off while feeding Kayla in the NICU, they knew we were having a good feed LOL.