I have gone back to work twice while bfing so it can be done, and usually works out being easier than you expect. For me I was able to build a stock of EBM up by starting weeks before I went back and building it up. I also expressed at work although I didn't always get enough milk from that for the next day so a stockpile is good. Babies generally drink less when than they are away from mum and then make up for it when you get home so you might find you need less EBM than you are expecting.

It does concern me though that you are not planning to express while at work. From a supply point of view that is not likely to be a huge problem - your supply will adjust so that you make more milk on days when you are bfing all day and less on work days - our bodies are truly amazing!! However at first you will be very full and uncomfortable if you try and go 8 hours without emptying your breasts and you will really be at risk of mastitis. Over time as your supply adjusts this won't be a problem, but for the first weeks at least you really will need to express - either by hand or pump - or have someone bring the baby to you to feed, at least once in 8 hours but at more likely twice. I'm sorry to throw a spanner in the works. Do you think you can come up with a plan b?