Well, what I think happened is that you whited (whiteyed, what ever you wanna call it). You usually go a light shade of green or VERY pale. And due to the whitey-ing your body got thrown into a panic attack. I hope you feel better, weed's supposed to be your friend, not your enemy!

edit: i've whited a few times. The first time I thought I was DYING, I was so sick to my stomach and hot and cold at the same time. I was literally green and I could hardly stand. not fun, I feel ya.