It may have been the grain.
When I was watching the Superbowl with my buddies, I decided that since
it was a special occasion [I know not for everyone :) ]I was going to
eat pizza. I ended up eating a half of a large pizza. By the time I had
finished, I develpoed a terrible headache. It was very similar to a bad
caffiene withdrawl headache- the kind that doesnt stop with medication.

I have eaten ice cream with no ill effects, so I would say grain causes
more of a reaction than dairy.

Your poundcake situation sounds like what happens to me. We've all kicked
the Carb habit, but for a long time we will still be addicts. When I eat
some carbs, it always seems like i end up binging till I get sick.

Ry