Unsure of Problem? Transmission, Perhaps? White Smoke Observed.?

I encountered a recent conflict with my 2002 Honda Odyssey during a road trip. As I was driving at a constant speed b/w 75-80 mph, at one point, my transmission odometer climbed from 2-5 very quickly; the pedals felt as if I had switched gears and shifted. Almost immediately, there was a great cloud of white smoke coming out from the hood. The white smoke had a foul stench in it, and at first, I thought something was overheated. Coolant levels seem fine. Engine oil levels were okay as well (there was no engine light on either). However, the transmission oil was literally gone and had lost its typical "pinkish" color; in place of it was a nasty, burned out odor. I do not know what happened. Later, when I re-fueled, and continued home at slower speeds (around 50-55 mph), the gasoline levels went down very, very rapidly. I went to Advanced AutoZone, and they suggested I replace a circuit sensor? in which I did. However, this still does not explain what caused the white smoke in the first place, or the possible transmission errors. Please help! Thank you.