I think you've somehow managed to e-infect me, Carl. I'm experiencing similar symptoms to yours... cramps, nausea, vomiting, and a really wicked headache that I can feel in my face, sort of behind my eye, and I can almost feel it in my nose.
It's definitely not withdrawal, and it came on fairly quickly; I came home from work, had about an hour before I needed to be in at my other job, but I felt warm, queasy, and fatigued, so I called out. It's a good thing, too, because an hour later and I was throwing up.
I sniffed a couple bags about half an hour ago, which, believe it or not, was not an easy thing for me to do; just thinking about the drip made my stomach do somersaults.