Bad nausea after lower ab workout?

Every time I exercise my abs, there's a sharp pain in one spot of my stomach. Right now I'm feeling really nauseated, and I've already gagged. I feel like I'm going to throw up. Also, I'm having lower stomach pain that feel like cramps.. I'm also having that cold chilly shaky feeling you get after you vomit.. I'm not sure what's wrong. But it's a horrible feeling.. Anyone know what could be the problem?