How do I explain my celiac disease at work?

Dear Gluten Dude

I was diagnosed with celiac disease after I already began working from myself and working from home. So those days where celiac just got the best of me, I was able to shut it down. But what about if you work at an office? How do you explain to them that there are going to be times where celiac just kicks your butt and you won't be at your full capacity? That's the dilemma in today's Dear Gluten Dude. Here's the email:
"Hi Gluten Dude. I've been gluten free for seven years now, ever since I got the call from the doc letting me know that I have celiac disease. Initially I did not handle the news well; in fact I ate a piece of Pizza Hut pizza about an hour after the phone call. Nowadays, I know the drill. I know that just a little bit of gluten can put me down for days. I also know that even though I've been gluten free for seven years, I still have a disease and it still impacts my body.

There are days when I just have no energy, there are days when I'm curled up on the couch, unable to move because I was the victim of accidental cross contamination somewhere. I'm vigilant, but as you know, there is only so much a person can do.

So, my question is this, how to you deal with an office/work environment? How do you explain that yes, following a GF diet pretty much keeps you healthy, but it isn't foolproof and sometimes you just need to take a break. How do you explain that you are perfectly capable of doing your job, but that you can't work 60+ hours a week. Thanks, Gluten Dude. Thank you for being an advocate for our community! "
My first thought? You better be getting paid for 60+ hours a week. My advice? Tune in.