If I had to guess, I would just say that it was a stronger type of chronic that you weren't really used to. Also, I thought that it was the fact that you were eating brownies instead of smoking (it hits you harder when consumed like that) but then you said that you had done brownies before.. hmm... I dunno. It was probably just stronger bud. Just know your limits to what you can be exposed to (try smoking bud, it's a completely different feeling!). Hope it helps!