It is very doable. I went back to work full time at 6 weeks and EBF until DD was just over one year old.
By the time I went back to work, she was on a bit of a predictable schedule. I pumped at work at roughly the same times she ate (around 10, 1, 4). I sent three bags of BF to daycare each day and made sure they had an extra bag or two in case one spilled or DD was extra hungry.
Get a good pump-I had the Avent Electric and the Medela PISA and loved them both. I left one at work and one at home, that way I never worried about forgeting it. Check with your insurance, my OB gave me a coupon for a free PISA and said it was part of the Affordable Care Act.