I felt like I was attached to my nursing chair for the first couple of months because my daughter was a slow feeder - I would nurse for 45 minutes and then 15 minutes later she's want to nurse again! Then going back to work I had to pump too which was a pain but I was lucky that I had an office to do it - a friend of mine had to use the shower in the company gym because she was in a cubicle. All I have to say is, you are really in the home stretch here. If you nurse to 6 months, the rest is cake! Your baby will start eating solid food and you'll nurse less, which means you'll pump less, if at all. You could even switch to formula just for the time you're at work so that you don't have to pump anymore. By the time you're where you are, or maybe 5 months in, your supply should be able to handle reduced nursing with no problem.
If you wean now, a few things - one, your baby will not be able to fight off illnesses or deal with them as easily, two, by breastfeeding to a year you are lowering the risk for you and your child from certain forms of cancer, three - nursing is my "magic bullet" - it comforts my daughter when she is upset or sick, it helps her fall asleep, and when she quit bottles at 6 months with no warning, I was really happy she was still nursing! she's been on sippy cups since then, and now I don't need to wean her from a bottle. When we fly on planes, she nurses on the way up and down which helps her ears pop and she SLEEPS most of the way. People comment that they didn't even know a baby was there.
And finally, I was not a huge fan of breastfeeding before I did it. I'm still not comfortable doing it in public, so I just don't (we did bottles or sippys in public, though I've done it in the mothers room at the mall or in the maternity store when need be). I didn't think I would feel like I needed to do it to a year and beyond (my daughter is now 12 months) especially early on when she wouldn't latch and I needed to use a nipple shield for the first three months, but I can't imagine losing the closeness that nursing had given us. We have a friend whose baby feeds himself his own bottle and has been doing so since 5 months - they just put him in his carseat, bouncy chair, high chair, and he just feeds himself . I'm sure that it's really convenient because they can do other things while he's eating, and I'm sure they cuddle him plenty at other times, but I can't imagine doing that with my daughter - she loves her nursing cuddle time with mom and it forces me to stop what I'm doing and RELAX for just a little while to connect with her. We're always so busy and want to be doing, doing, doing things - I really need the break too.
So I vote stick it out - it gets better and it was worth it for me. Can't speak to everyone's situation though so I'd weigh all the opinions and your own feels and do what's best for you and your baby. Remember though that it doesn't need to be all or nothing - you can nurse in the morning and evening and do formula during the day... :-)