I'm not doing so swift myself (that's another story) and I'm getting lots of helpful advice here.
I have heard before that cats and dogs are allergic to cocoa, not people. Don't freak out.
Anyhow, I don't know squat, but I would probably go ahead and throw up if you can, do an enema if you can't (make sure the bag and tubing aren't moldy, or you'll really be in a mess) and I would bet you need to flush with lots of good water (with a little celtic or himalyan salt). If you have any green drink, that would probably be good too. People who know more than me will post soon, I'm sure. I'd guess there are some herbs to settle the racing heart. Breathe deep till you hear.
I'm just going by the advice I've gotten just recently--my stupidity went in the other end. I'd say you may be reacting to the caffiene.