Getting sick while working out!

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I have been attending a step class for about 3 months now and today at the end of my workout (beginning of cool down), I got so hot to the point where my instructor took me to the bathroom and I got sick, a lot. Any ideas on what happened? I drink only water, so I do not believe I was dehydrated. The only thing I did differently was I placed extenders under my board. Do you think I may have over exerted myself?