I had a similar experience in Boston one year. I was on the 40th floor of One Boston Place, near city hall, and there was a pretty bad wind storm moving through. We get those from time to time... just a freak burst of 60 mph winds with little or no storm associated. It's rare, but it happens.
Anyway, the building was swaying and during the course of the day two things happened which I found amusing. First, we had one of those big green LED signs with news tickers scrolling over it. It was suspended from the ceiling by two cables and it was swinging back and forth dramatically. A co-worker had been looking at it somewhat queasily, and asked, "why is it moving so much?" In retrospect, she was looking for a comforting answer. I just thought about it for a second and gave her the most logical answer I could think of: "It's not." That took her a second to process and then she looked very unhappy.
The other thing that happened was kind of unnerving to me. I was sitting in my chair, working on some code, and I stood up to get something. Next thing I knew, I was on the floor. I tried to get up again, and bang, I was on the floor again. My inner ear had just given up, but I had no idea until I tried to stand. It was odd because I'd spent years around the ocean, and never got sea sick or even a touch nauseous, but in this building I was incapacitated for a short time... no other symptoms, just the complete lack of balance.