Thanks for the advice and concern. I worked 2.5 hours this morning and then went to the chiropractor. I'm feeling pretty good. Of course, my "working" involved mostly walking around, talking, and drinking coffee. It wasn't exactly stenuous.
The funny thing is that I thought sitting would be the hardest. But it was some of the weird daily things that hurt- like scanning documents through the scanner when finished with them. It's on the left of the computer and it strained me to try to use it. When I go back for the second 2 hour time, I'll sit at a coworker's workspace and use her set up, as her scanner is on the right and I think it'll be totally different.
It's amazing how people see you and don't "see" you. Well, I guess I mean me, not "people. Several sympathetic coworkers told me that they know how I feel, and they have shared stories of their experiences. You know, I've known some of these people for 20 years, and never knew of some of these struggles with pain and back problems. I guess I never looked beyond the friendly smiles and friendly chatter, and I'm feeling really bad about that.