Like most people said, it was just some strong stuff and you hit it too fast. The same reaction happens to even veteran smokers at times. If I quit for a month and then start smoking again, I get the shakes and my heart starts going crazy. Once I center myself enough to realize that it's just the weed, everything calms down...about 10-15 minutes.

I would definately pack a bowl, smoke a hit, then give it a few minutes. Guage how it's making you feel. If you think you can handle more, then repeat. Otherwise, flag yourself and call it quits. It's kind of like alcohol...you drink responsibly and being drunk can be a good thing. You take it to fast, and well, your face is in a toilet all night.