Hahahaha oh god, that was a pretty strong reaction. Mine have been always lesser in degree but it's the same symptoms. 4 brands of Kelp I tried so far (IIRC). 1 of them terrible headaches, the other 3 the manic state you just described.
I'm wondering why the hell this happens. I had a similar reaction not many days ago when having a soup that had small pieces of kombu on it.