To me it sounds like you tired yourself from walking up five flights of stairs.
I find if I am forced to exert myself in this sort of way, I can get nauseous, and this lasts for hours. It's very unpleasant, and I do everything I can to avoid such activities. Walking slowly on a level path is generally ok, but having to climb stairs is akin to trekking up Everest!
I expect what you experienced is simply a reaction to the exertion, and the only solution would have been to lie down and rest until the feeling passed.