After swearing I'd never eat anything from McDonalds again (especially since I wasn't feeling so great in the first place), I had lunch there today as I needed a wi-fi connection and they were closest. However, I had to buy something consumable in order to use the Internet (this particular location has a problem with the local homeless population coming in and loitering). I order a Royale with cheese "value" meal and then proceed to eat and check on some personal business.
You could have tied a giant block of granite to me as walking the block and a half back to the office felt pretty much the same. And of course, all I wanted to do when I sat down at my desk was die. Still feeling pretty crappy, thanks for asking. A lesson learned for me becomes a safety tip for you.