I've always heard that if you get food poisoning you'll know it...but can you get just a slight case?

I've been on a long, long stall, so I decided to go back on induction this week. Tuesday I had a piece of steak for lunch. It was the last in a package and the color looked a little "off", but I figured it was just air reacting to the dye (was that stupid???) As soon as I had eaten it I began to feel very, very strange. Sick, weak, red in the face/feverish, stomach pain, nausea. I never vomited, though. (I'm typically resistant to vomiting for some reason.)
Then I developed a horrific headache, which is untouched by tylenol, advil or aspirin. It hasn't let up yet (Thursday) and my stomach is still unstable. I've been eating, but feel crampy afterwards and just generally awful.

Does this sound like a slight case of food poisoning? I'm afraid I'm not going to want any more steak for a long time...and I'm dying for a cracker!