Apparently, I messed up my electrolytes. I haven't been to a doctor, but it took me about 24 hours after the meet, with a lot of eating and sleeping in there, to feel back to normal again. I think I was lacking in salt, potassium, and other essential things simply because I was eating less, and because I had tried to cut back on salt in order to maximize weight loss.
Lesson learned. It took having my favorite take-out Chinese food dish last night to bring my body back into balance.