Here's one more success story for you:
I went back to work full time when ds was 13 weeks. He is now 27 months, (and I am now part time, but that's sort of irrelevant) and still nursing like a fiend.
I used the Medela Pump in Style, and because I was at the time working as a resource teacher, I traveled school to school and rarely had access to a fridge or hot water. I used the cold packs to chill the milk and an electric kettle when I could to clean the pumping stuff, when I couldn't I just was sure to sterilize at home.
3 days a week ds was in daycare nearby and I nursed him during my lunch breaks. The other two days he was at home with dh and I just pumped.
It was hard for me, but my situation at home and at work at the time was very stressful. Towards the end of the school year I couldn't pump enough to keep up with ds and I had to bring him what I had pumped in the a.m. for his afternoon. Part of the problem, I later discovered was that one of the tubes on my ump was working its way loose and I wasn't getting good suction! Yikes.
But, we made it and never had to supplement (not that that's bad, but it was important to me for a number of reasons.)