What the weakness?

I think I might be getting sick. Which would be horrible timing. Heinous. Ridiculously inconvenient and quite problematic. I hope that such is not the case. But, I am noticing that I am uncharacteristically weak and prone to disorientation/imbalance. For example: When I rode the elevator up a floor, the momentum/gravity made my knees bend, and I could regain an upright position again until the elevator stopped, and I had to use the hand rail on the side. Also, I found it exhausting to plug in my laptop cord. Seriously? When I lean my head back, I have to use my hands to get it back up, and then I feel faint and dizzy. And standing up tends to be a little challenging too. Anyway, I need to get back to lesson preparation. I think that I will let my class out early today. I hope they don't mind :)