How's being back at work?

Strangers, acquaintances, even friends ask the general "how are you?" or "how's work?" question. Sometimes it's in passing; sometimes it's for real. I don't really know how to respond appropriately given the time constraints and the truth. I'm supposed to just say, "good thanks," and leave it at that. But, that's really a lie. Sure, things are fine, but occasionally I launch into a longer than desired response about how it's hard and why. When I feel like being just a little honest, I say, "you know, it's hard, but it is what it is." This way I'm not lying, but I'm not delving all the way in.
So, what is the appropriate response? Who should I be honest with and who should I brush off? Better yet, why do people ask such an involved question. The "how's your baby?" question I can handle. That's easy. So the next time someone asks me, I'll just refer them here so they can read it.
How's being back at work?
It is really challenging. Every day it's a struggle to leave my baby girl early in the morning. I get up by 6, cover the under eyes with concealer, hydrate and fuel with caffeine and cereal, squeeze into some pants (getting better), make a lunch, pack my pump bag with the necessary parts, hope my hair looks acceptable after a quick brushing and then I get to feed her. I listen to her breathing and happy eating sounds. She cups her hands near her face. I savor the moment and commit it to memory. As soon as she's done, I hand her off to daddy for burping, and I'm out the door. Some days involve a quick extra pumping before the morning commute.
During the day, I'm honestly so busy that I forget what I'm missing for a few moments. I rush rush rush to get things done. By 10:08 it's time to pump. I spend 15-20 minutes looking at pictures of her and focusing on getting milk to flow. I clean up, wash pump parts and rush to get things ready for my afternoon classes. Teach some more and by 1:51 I 'm pumping again. Even though it's a hassle, it's the time that I devote to her while I'm away. I look forward to it, because I get to feel that connection with her and know that I'm doing something good for here while I'm gone. By 3:31, I'm packed and out the door. I've been trying to get home for her 4:00 pm feeding and most days I've lucked out. We play for an hour or so before she naps again. I push the thoughts of work out of my mind, wishing I didn't have to do it all again the next day. Maybe someday I won't have to.