At such a dosage it is definitely something easy to expect - you overdosed on this supplement, so you got some side effects. Use the proper dosages always, even on supplements, as everything can cause considerable side effects when overdosed.
It's because of all the stimulants in the product. It would be equivalent to drinking an entire pot of coffee in one sitting. Stick to there recommended dosage of 1 scoop pre-workout or use a stimulant free pre-workout like d-spark from n2bm.com.
I'm surprised you didn't shit your pants. That amount of pre workout powder can't feel good on the stomach not to mention what it would do to heart and blood pressure.